What is an electromagnetic car suspension

The car's suspension is quite conservative. Despite the improvement of its individual components, the general principle of construction does not change. Elastic elements and dampers on hydraulic and pneumatic elements, complex mechanics of the guide vane. The work here can be radically improved only by using active performance management, monitoring changes in the road profile and load at high speed.

The history of the creation of electromagnetic suspension

One example of the use of electromagnetic field energy is electromagnetic suspension, which is one of the types of car suspensions and has found active use today.

Few people know, but the first scientific works explaining the principle of the magnetic field came to us even earlier than the internal combustion engine was used.

The first mention of an outlandish device that uses physical laws previously beyond the control of humans belongs to the theoretical works of the English physicist and inventor Michael Faraday.

This legendary scientist, back in 1862, was the first to explain and lay the future foundation for the thinking of many minds around the globe.

The second progenitor of the creation of electromagnetic theory is another British scientist, James Clerk Maxwell. Although his main layer only indirectly explained the principle of the influence of the electromagnetic field in nature, his work will largely predetermine the development of this movement, as well as all of physics in particular.

However, the first practical successes in the design of the automotive industry based on electromagnetic influence were achieved only in 1982. Then the first prototype of a train using a magnetic levitation was built.

The M-Bahn was a truly unique reflection of the ideas of great minds, but its application in a wide area was impossible due to its imperfections.

German magnetic levitation train - M-Bahn magnetoplane

Having drawn public attention to the realism of such an invention, many engineers, realizing that a full-fledged “floating” transport is still only a dream, concentrated on creating less significant but practical automotive designs. As a result, in the 1980s, Bose was the first to produce electromagnetic car suspension, using the necessary calculations and calculations.

Unlike standard mechanical suspension, electromagnetic suspension cannot be used separately on different axles, but works in a coordinated system on two simultaneously.

System composition

The complex includes devices that provide control of damping properties and dynamic rigidity, as well as minimizing body roll:

suspension controller with microprocessor, memory and input/output circuits;
active roll countermeasures (controlled anti-roll bars);
complex of sensors;
shock absorbers allowing electronic stiffness control.

Using the dashboard controls, most often this is an on-board interactive display, the driver can set one of the operating modes according to his preferences. Predominance of comfort, sportiness or off-road ability is allowed, as well as more advanced individual settings of functions with mode memory. The accumulated adaptation can be quickly reset to the original settings.

Requirements for transverse stabilizers are always contradictory. On the one hand, their purpose is to ensure minimal body roll. But this way the suspension becomes dependent, which means comfort decreases. When driving on bad roads, a more valuable feature will be the even greater freedom of the individual wheels to achieve maximum axle articulation. Only in this way will all suspension travel reserves be fully utilized to ensure constant contact of the tires with the coating. A stabilizer with constant stiffness, which is usually a simple spring steel rod operating on the principle of a torsion bar, cannot serve equally well in all conditions.

In active suspensions, the stabilizer is split, with the possibility of electronic regulation. Various principles can be used to control the reduced stiffness. Some manufacturers use preload torsion using an electric motor with a gearbox, others use a hydraulic method, installing hydraulic cylinders on the stabilizer or its attachment to the body. It is also possible to completely imitate the stabilizer bar using individual hydraulic cylinders operating in parallel with elastic elements.

Adjustable shock absorbers

A conventional shock absorber has the property of changing its dynamic stiffness depending on the speed and acceleration of the rod movement. This is achieved by a system of throttling valves through which shock-absorbing fluid flows.

For operational control of bypass throttles, two ways are possible - installing spool-type electromagnetic valves or changing the properties of the liquid in a magnetic field. Manufacturers use both methods, the second less frequently, since it requires a special liquid that changes its viscosity in a magnetic field.

Basic elements of magnetic suspension.

Each electromagnetic suspension consists of a specific set of components that ensure the fulfillment of its main task:

Elastic structures with the ability to receive and transmit vertically applied forces.
Guide structures that form the pattern of movement of the wheels of a vehicle, as well as ensuring the connection of the wheel row with each other. The guides are also responsible for receiving and transmitting forces applied horizontally.
Shock-absorbing elements, the main task of which is to reduce the force of vibration of the body when moving on the road surface.

Conventional representatives of modern suspensions consist of many elements, each of which can perform a wide range of tasks. But at the same time, these are amazingly complex mechanisms, each component of which has unique properties. This approach to suspension production technologies provides a good increase in vehicle controllability, comfort and stability.

EM suspensions also have all of the above components, only in a more advanced, technologically improved version. Magnetic suspension is a special mechanism, the basis of which is an electric motor. The engine has two running modes, ensured by the presence of an elastic and damping element. A special microcontroller is responsible for switching between them. Due to this design, the EM suspension is capable of playing the role of a conventional automobile shock absorber.

Advantages and disadvantages

Electromagnetic suspension is a completely new word in the automotive industry. That is why comparison with standard suspensions is, to say the least, incorrect.

If we talk about its advantages, then for the driver they are more than obvious:

The softness of the car's chassis.
The control is carried out using an on-board computer, which in itself is not new. However, many drivers note that the automated system is more responsive, which improves control.
There is also a definite advantage in saving energy consumption.
Multifunctionality - it can work automatically and then switch to mechanical mode. Such multitasking can significantly increase the reliability of the vehicle’s chassis, as well as driving safety in general.

On our website you can read about air suspension, which also has many advantages, one of which is the ability to adjust the ride height.

If we talk about the disadvantages of this type of suspension, we can name one - the availability of software to control this system. But progress does not stand still, and work in this direction is in full swing. Therefore, we can expect mass production of this suspension part in the near future.

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I would also like to note the fairly high cost of such a chassis. It has not yet been put into mass production, but we can already name an approximate price tag - about 250,000 rubles. In principle, for this money you can buy a pretty good used foreign car, but no one said that modern suspension is intended for economy-class cars.

This is a fairly new technology in the automotive field that will be used in expensive cars, so such a high cost is quite justified.

We can already say that the appearance of electromagnetic suspension has become a new milestone in improving the driving characteristics of a car. This system is currently intended for the front suspension, but technical capabilities allow us to significantly expand the possible implementation of this system in a car device.

Other areas of the electromagnetic system are also developing. In particular, some models act as an electric generator, which allows you to convert all the bumps in the road into full-fledged energy. In other words, a car drives along the road, and every bump or pothole on this surface is a source of electrical energy.

This seems fantastic, but now we can safely say that the future has arrived today.

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What you need to know about electromagnetic suspension

The units and elements that use electromagnetic interaction between their components work the fastest.

Such devices are able to respond as quickly as possible to external influences, receiving commands from an electronic controller.

Principle of operation

It is known that like poles of magnets repel each other. If the magnets are electrically activated, then such a device is called an electromagnet. By changing the amount of current passing through the windings of electromagnets, you can regulate the force of their repulsion.

All this allows the use of a structure of two or more magnets as an effective and high-speed spring, since the external effect is completely identical to a steel spring or its spiral analogue - a spring.

The resulting electromagnetic spring has the extremely useful property of instant response to control input. It is impossible to achieve such a speed in any other way; hydraulics and pneumatics have delays measured in seconds, which is unacceptable for a quick change in instantaneous stiffness.

Having such a powerful tool in the suspension, designers can only build an electronic control unit, equip it with the necessary set of sensors and develop the appropriate software for the control microcomputer.

Theoretically, this task is easily accomplished, although in practice certain difficulties arise. As usual, it all comes down to the price of the issue. Especially when it comes to large-scale production. You can create a perfectly working system, but in mass production it will not have the necessary competitiveness.

Another way to introduce electrical engineering into the suspension is to use it in the damping elements of a more traditional hydraulic design.

There are two ways to do this:

control electrohydraulic valves through which the shock absorber working fluid flows; reducing the cross-section of the transition hole leads to an increase in the effective rigidity of the unit and vice versa, the shock absorber works softer if the oil flows freely in it;
the same effect will be achieved by changing the properties of the liquid itself under the influence of an external electromagnetic field; such mixtures exist; they use the principle of spatial orientation of ferromagnetic particles.

The second method gives greater performance, but is also more expensive, since such liquids are high-tech and difficult to produce.

What elements does it consist of?

Today, three companies dominate the market:

Naturally, the design of each suspension mentioned will be different.

Delphi's electromagnetic is a shock absorber consisting of a single tube filled with a substance including magnetic components. They make up 30% of the total volume of the required liquid, and to prevent it from spilling out, there is a special coating in the chassis.

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The electromagnet is a piston head controlled by an on-board computerized system. The SKF electromagnetic is a capsule with two electromagnets.

When the car is in motion, the system begins to analyze the information and, if necessary, can change the fluid of the damper element, depending on the information received from the wheel sensors.

The Bose suspension is considered the best design of this type. It is a linear type electric motor with several modes:

damping element;
elastic element.

This is the rod on which the magnets are located. When the car is moving, the rod performs motor manipulation along the entire length of the stator. This circumstance allows you to feel very confident even on rather uneven roads.

Manufacturers

Like any other product in the automotive industry, electromagnetic shock absorbers are produced by several different concerns. Apart from the marketing name, devices from different manufacturers are based on different technologies. There are three leading companies producing electric suspensions, each of which produces products that work on a different principle from the others. We'll take a closer look at all three companies and look at each product.

Bose electromagnetic suspension.

The history of this technology begins back in 1980. It was in the early 80s of the last century that the outstanding professor Amar Bose, who teaches at the university in the department of electromagnetic phenomena, created his first product. He carried out countless calculations, and, after systematic analysis of the data, obtained the optimal shape and characteristics of the car suspension. Since Professor Amar Bose was also the head of the Bose company, his research made it possible to create a new type of pendants that exploit the principles of electromagnetism. The experiments of the outstanding scientist attracted wide public attention and directly influenced the entire automotive industry market.

The Bose suspension, completed and improved by the company, is considered the standard of magnetic suspension. According to the tests carried out, they cope with the assigned tasks almost one hundred percent - they level out the level of any fluctuations that arise. The main component of the product from the Bose organization is a linear electric motor that operates in two modes:

As an elastic component.
As a damping component.

The permanent magnets included in the design ensure reciprocating movements along the entire length of the stator winding. This technology not only reliably protects the car from vibrations in the plane, but also improves its handling to an unimaginable level.

"SKF" on electromagnetic shock absorbers.

This product, which has high levels of simplicity and reliability, was first released in Sweden. As the main element of the SKF design, a special capsule is used, the components of which are special electromagnets and magnetic shock absorbers.

As the vehicle moves, the main computer receives data from sensors installed on the wheels, reading their characteristics in real time. The same computer is responsible for transmitting signals that change the fluidity of the damping structure. Also, the SKF product implies the presence of springs included in the design in order to level out vibrations in the event of a main computer shutdown.

"Delphi" with single-tube magnetic shock absorber.

The main component of the Delphi product is a monotube electromagnetic shock absorber. Its internal part consists of a special magnetic substance (suspension), the dimensions of which range from 3 to 12 microns. There are approximately 30% of such parts in the product; the rest is occupied by an electromagnet in the form of a piston head and a special coating that prevents the substance from spilling out. The electromagnet is also controlled from an electronic unit, automatically. At the moment the magnetic field is applied to the substance located inside the shock absorber, the following happens: the particles of the substance take on a special, ordered structure. Thanks to this, the viscosity of the substance increases, with the help of which the operating mode is switched.

Advantages of electromagnetic suspension

Although the main purpose of the electromagnetic suspension is similar to the classical one, it would be at least incorrect to compare them, since these are different devices. However, the advantage of the electromagnetic one is felt after a few meters of driving, especially when it comes to Russian roads, where, like nowhere else in the world, it is convenient to check the comfort of the suspension and the car as a whole. What immediately catches your eye, or rather is felt by the fifth point, is the smoothness of the ride and vibrations of the car, and what is most interesting is that this does not affect the stability and controllability of the car. If we take, for example, two contradictory indicators of any suspension - control over the behavior of the car and the comfort of the passenger and driver, then such a problem does not exist with an electromagnetic suspension. This system combines excellent handling, roll resistance and comfort for all vehicle passengers. Plus a high speed of reaction to changes in the road surface or driving mode.

Principle of operation

We have already said that the design of the part does not have elastic springs, so they are replaced by a system consisting of electromagnets. Control is carried out using an on-board computerized system.

To put it simply, the driver can evaluate the performance of units and wheels while driving a car. The system is improved and automated compared to conventional suspensions, because it can independently send signals to make certain adjustments in performance.

Disadvantages of electromagnetic suspension

There are two main disadvantages of the electromagnetic suspension, and one follows from the other and brings along another factor. The main disadvantage of such a suspension is the price (approximately 200-250 thousand rubles) and the lack of mass production. It is not mass-produced because the level of demand is low due to the high price, and the price is high due to piece production (one might say exclusive). This is such a vicious circle. Experts say that the cost reduction may be facilitated by the emergence of new production technologies or the introduction of cheaper, but no less effective materials for the manufacture of suspension. One way or another, those eager to change their suspension to an electromagnetic one will have to wait or save up.

Sensors

These are devices designed to measure and collect data that is necessary on the on-board computer to change the settings and parameters of the suspension if necessary.

We hope we've brought a little more clarity to the question of what active suspension is, but let's look at how active suspension works in general.

Imagine that you are driving on the highway and your ride is relatively smooth (as smooth as a normal highway can be). However, one day you decide to leave the highway and take a third-class road littered with potholes.

If you have a standard suspension, you have no choice but to see that vibrations in the cabin increase and your car will bounce more often and more unpleasantly. You should also be careful when driving and drive slower and more carefully, as there is a danger of losing control of the car over any bumps.

However, if you have an active suspension, this change in the type of road surface you're driving on won't affect you at all, because as soon as you leave the highway, you can simply re-adjust the shock absorbers and they will become "firmer". or vice versa - if you are driving on a bumpy road on the highway, you can re-adjust the suspension so that it becomes "softer".

All this is possible thanks to the active suspension, which can automatically adapt to your road and driving style.

Of course, as we mentioned at the beginning, how much the suspension can adapt depends on whether it is active or adaptive. In the first case, you can adjust the entire suspension, and in the second, only the shock absorbers.

Types of magnetic suspensions

Different development companies went in their own directions, guided by internal programs and ultimate goals.

It is customary to highlight suspension concepts from the American company Delphi Corporation, the famous Swedish company SKF and the idea of Professor Bose, whose name in the company name has become synonymous with high-quality acoustic systems for cars.

Delphi

The relative simplicity of this system does not mean that it is primitive or ineffective.

Despite the fact that the electromagnets here only control the properties of the shock absorber fluid, precisely influencing the instantaneous stiffness of the damper gives the suspension completely new properties. The rate of change of shock absorber characteristics here is many times higher than that of traditional active hydraulic dampers.

This is achieved by a special liquid that changes its viscosity so accurately and effectively under the influence of the control current of the electromagnet that there is no particular need to change the rigidity of the elastic element.

The strong dependence of suspension performance on the properties of the shock absorber has been known for a long time; their selection is given special attention in motorsport, where every second of the car’s stay on the track is crucial. Spring characteristics are not that important.

The Delphi electronic suspension shock absorbers use a fluid developed by the company with microparticles that can line up along magnetic field lines, dramatically changing the way it flows through calibrated holes.

Particle dimensions measured in microns allow achieving high speed due to minimal inertia. The same quality is ensured by minimal current consumption by the magnet windings, which is very important for the overall efficiency of the car and the simplification of power electronics.

The necessary information is taken from suspension sensors and other vehicle systems and processed in the electronic suspension control unit.

SKF

The Swedish company took a different route. Without touching the hydraulic shock absorbers, all attention was paid to the rate of change in the characteristics of the elastic element.

For this purpose, a special capsule containing two powerful electromagnets was integrated into it. By changing their interaction field, you can react to the situation so quickly that this device can act as both an elastic and damping element.

After all, the essence of damping is a dynamic change in rigidity, up to a change in the sign of the force vector from repulsion to attraction. In this way, the computer can dampen any fluctuations, as long as there is enough speed and range of change in the force of interaction of electromagnets. And these are questions of technological execution.

The power consumption here is significantly higher than that of the purely static operating mode of the electromagnets of hydraulic active shock absorbers.

But it does not increase to unacceptable values, in fact compared with more traditional consumers such as a climate system or an electric heater, and in order to avoid complete suspension failure in the event of electrical equipment failures, traditional springs are retained in the suspension, partially redundant electromagnetic equipment.

Bose

Professor Bose, who studied acoustics a lot, towards the end of the 20th century, became interested in the idea of creating an ideal car suspension. Unsurprisingly, the actuator is a bit like the greatly enlarged electromagnetic system of a large dynamic loudspeaker.

But what is really common here is only the use of a device that is theoretically a linear electric motor. That is, if we compare this with the development of SKF, then the number of electromagnet poles has been increased many times. They are located on the rod and stator of a device resembling a telescopic shock absorber.

The magnetic output of the unit is quite large, which made it possible to get away with acceptable control power, but the performance is such that the resulting “speaker” is able to dampen any processes, from stationary to oscillatory, working like a spring and a shock absorber.

It is enough to generate and apply a control signal to the windings, for example, similar to the external influence, but with the phase rotated by 180 degrees. That is, to completely extinguish unwanted vibrations by superimposing the same ones on them, but in the opposite direction at each individual moment in time.

This suspension is so effective that it can be considered the standard among all electromagnetic devices. The suspension can provide a uniquely large working stroke, about 20 centimeters, which is extremely large for civilian vehicles, excellent stability of the body position, clear reactions to any profile at any speed, and the absence of dives and rolls.

The very first presentations of the system on Lexus test cars literally stunned automotive journalists, although these cars have the highest smoothness as standard.

How does it work

It’s good to clearly illustrate how a car’s electromagnetic suspension functions using the example of one of its most successful examples – the Bose brand suspension. In it, the main function is assigned to a rod equipped with a magnetic “heart”. It is located in a magnetic field created by a linear electric motor. Due to changes in its characteristics, a rapid change in the elasticity parameters of the suspension itself and the car body is ensured. All this is achieved with enormous speed of reaction to external circumstances. The driver constantly reads all the necessary information from different sensors installed in different places of the car.

The reduced number of mechanical components provides the entire structure with high service life. The smoothness of the car's movement is much higher than in the traditional version.

Purpose of elements

Despite the profound differences in operating principles, all electromagnetic suspensions have many common elements:

a system of sensors that record the movement of the wheels relative to the body, as well as monitor the condition of the road in areas that the wheel has yet to overcome in order to react in advance to irregularities;
general-purpose sensors that collect information about current driving parameters, speed, driver reactions, etc.;
an electronic control unit with a microcomputer that collects, analyzes and processes information into control signals;
power electronics that generate powerful currents in the windings of electromagnets;
linear electric magnets that create the necessary mechanical forces on the rods of the suspension elements;
executive and guiding units of the chassis.

In addition to the visible nodes, the system contains an equally technologically advanced software product, under the control of which everything works. Its role in the overall complex is no less than that of the suspension elements.

General information

What is the suspension in a car?

This is a kind of intermediate link between the body and its wheelbase. The chassis provides the connection between the axle and the frame, as well as with other components of the vehicle.

In the design of a car, the suspension plays a vital role, because it transmits torque from the wheelbase. As a result, the car elements transmit the required motion vector to the wheels.

As for the electromagnetic suspension, one of the characteristic features of its design, which distinguishes it from standard suspensions, is the fact that it may completely or partially lack torsion bars, springs and other attributes of a conventional chassis.