In Liu Cixin's "Ball Lightning", such a scene is described: under the attack of electromagnetic pulses generated by several ball lightning, human civilization suddenly regressed to the "era of cold weapons". All electrical appliances on the earth have failed, cars have fallen asleep, planes have crashed directly, and aircraft carriers have become scrap metal at sea.
Some people say that this is a sci-fi scene. But in reality, electromagnetic interference has become an "invisible killer" in military warfare.
In 1967, such an accident occurred on the deck of the then American supercarrier USS Forrestal. Due to unknown electromagnetic interference, the fighter planes parked on the deck automatically fired rockets and hit the fuel tanks of another fighter, and finally the fire became uncontrollable, resulting in 134 deaths, dozens of warplanes scrapped, and $1.4 billion in losses.
In fact, in modern warfare, "electromagnetic countermeasures" have become a key link in whether or not a war can be won or not, and it plays a vital role. Taking the Russian-Ukrainian conflict as an example, the Ukrainian army invested a large number of drones in the battlefield, but they were later directly destroyed by the Russian army with high-power electromagnetic jammers.
As early as the 90s of the last century, the US military began to pay attention to electromagnetic warfare, and the shadow of large-scale electromagnetic warfare can be seen in almost every overseas medium and large-scale military operation. Once the adversary is subjected to strong electromagnetic interference, communications and command will be greatly affected.
Of course, electromagnetic interference is not only used in military warfare, but also affects our daily life all the time.
The reason is simple, where there are electronic devices, there is electromagnetic interference, and cars are no exception!
Electromagnetic interference: the "invisible killer" of automotive intelligent safety
We all know that today's cars are becoming more and more intelligent, in addition to the battery, motor, electronic control of the "old three electrics", there are refrigerators, color TVs, large sofas of the "new three electrics", as well as intelligent driving, intelligent cockpit and other intelligent systems.
These systems are more susceptible to electromagnetic interference due to the fact that they have a variety of sophisticated electronic devices built in, such as telematics control modules, infotainment systems, navigation systems, connected devices, instrument display systems, and more.
Moreover, the electronic interference of the car does not only come from the electronic devices in the car, but also from the outside. For example, radio stations, television stations, base stations, etc. in the city will cause certain interference to the electronic equipment in the car.
And once the electromagnetic radiation is too large. At worst, there will be common phenomena such as screen flickering and audio "sizzle" noise. There are also rumors in the market that electric cars make people lose their hair, also because of the influence of electromagnetic radiation.
In addition, electromagnetic interference can break down electronic devices, directly causing damage or malfunction of electronic components. Imagine that once an electronic component does not work, it is very likely to bring wrong instructions or serious interference to the work of the entire module.
For example, it leads to inaccurate navigation and positioning, poor signal and so on. As a result, intelligent driving misjudges or even directly fails at work, and ultimately causes potential safety hazards.
Previously, a domestic research team conducted relevant experiments on "the impact of electromagnetic interference on automobile automatic driving". Among the 4 test vehicles, one ACC function was abnormal, and 2 FCW functions were abnormal.
This shows that electromagnetic interference does pose a safety risk to the automatic driving assistance system of automobiles, and the electromagnetic safety of intelligent networked vehicles cannot be ignored.
Speaking of which, some people may ask, what exactly is electromagnetic interference? Why does it have an impact on electronic devices?
Electromagnetic interference is actually an objective physical phenomenon that can interfere with the cable signal and reduce the integrity of the signal. Take a chestnut:
The honest young man "Electron 1 was working hard in his own electronic components, and suddenly there was a "beautiful as a flower" Electron 2. So, being attracted to electron 2 at the moment of electron 1, he stayed in his electronic components dishonestly and ran away with electron 2. As a result, the electronic components that work in Electron 1 fail! In this case, we can call it "electromagnetic interference".
However, Electron 1 was charmed by Electron 2, and you can't blame others for being "dishonest". Because as we said earlier, as long as there are electronic and electrical devices, electromagnetic interference will occur.
So, the question arises, since the impact of electromagnetic interference is so great, how can the car resist electromagnetic interference?
BMW: Add an "electromagnetic immune system" to the car
In the face of electromagnetic interference, BMW's approach is to add an "electromagnetic immune system" to the car, and this "immune system" is the powerful electromagnetic compatibility (EMC).
The so-called electromagnetic compatibility means that when the electrical equipment is subject to electromagnetic interference, it can still work normally, and the electromagnetic field generated during the operation of the equipment will not affect the work of other equipment in the surrounding environment.
You can understand it this way, electromagnetic compatibility is to allow electronic equipment or systems to have a "protective barrier", not only to prevent external attacks, but also to make one's own "not to go out and harm others."
So, how do you make your vehicle have better electromagnetic compatibility? Among them, manufacturers need to take effective suppression measures in all aspects of the design of automotive electrical components to reduce or eliminate electromagnetic interference.
At the same time, the performance insurance of the vehicle in the electromagnetic environment is evaluated through EMC electromagnetic compatibility testing to ensure that the design and function of the vehicle will not be interfered with by other electromagnetic waves. In other words, only cars that have passed the EMC EMC "exam" will be safe on the road.
BMW is the first luxury car company to start EMC testing. According to BMW engineers, EMC's history at BMW can be traced back to the 70-80s of the last century.
At that time, only the engine ignition coil and spark plug were the main sources of disturbance, and since there were no other electronic control components and units, there were few performance requirements for the anti-interference. Therefore, compared with the more complex working conditions in the military field, the early automotive industry did not have such high requirements for EMC.
But even so, BMW has set up an EMC laboratory. Because in BMW's view, all safety hazards should be "0 tolerance". Because of the advanced layout, BMW not only has the industry's most advanced and stringent EMC EMC testing technology and standards, but also has established the world's largest EMC laboratory, and the new BMW 5 Series is from here.
Check in to BMW's largest EMC lab in the world
Not long ago, Dianju came to the new EMC composite laboratory located in the BMW Chen's R&D Center in Shenyang. According to the engineers, this EMC laboratory was built by BMW with a lot of money, and it is the largest and most comprehensive EMC laboratory in the world so far. In addition, it is BMW's only EMC technical team and test center outside of Germany.
BMW engineers also told us that BMW's EMC laboratory has the electromagnetic compatibility and RF testing capabilities of the whole vehicle and high and low voltage electronic and electrical components, which can cope with the electromagnetic compatibility challenges brought about by the integration, intelligence and networking of electronic and electrical systems of new energy vehicles, so that every BMW car has passed the EMC electromagnetic compatibility test comparable to the aviation level.
In other words, in the future, BMW will be able to continuously test its own vehicles through its own EMC laboratory to find out electromagnetic compatibility problems, so as to ensure that each vehicle has a strong "electromagnetic immune system" before mass production.
Take the all-new BMW 5 Series, for example, which, according to engineers, has been tested in BMW's EMC lab for more than two years.
During the visit to BMW's EMC laboratory, the most impressive thing was the BMW EMC anechoic chamber, which was designed based on the all-in-one concept of combining EMC and intelligent network-related functional testing, and BMW called it a composite anechoic chamber. It has a special dimensional structure of 27m x 22m x 13m, which is also the largest automotive EMC chamber in the passenger car segment.
It can be seen that the entire wall and ceiling of its laboratory are made of materials made of special fibers and coatings to absorb electromagnetic waves, which are called absorbing materials in the industry, and the back of these absorbing materials is covered with galvanized steel sheets for shielding. The combination of absorbing materials and shielding technology creates a perfect environment for EMC testing.
During the visit, when the electric horse entered the laboratory, the mobile phone and any electronic products could not receive external signals, which shows that its effect on electromagnetic shielding is cured. BMW engineers proudly say: "We are very suitable for R&D and related confidentiality work here. ”
It is worth mentioning that BMW's EMC laboratory can not only conduct vehicle tests, but also test auto parts, such as its component-level anechoic chamber can conduct electromagnetic compatibility tests on power batteries. Therefore, driving a BMW's pure electric car definitely does not have to worry about the problem of "hair loss".
In addition, BMW has innovatively reserved the technical reserves and capabilities to expand antenna performance testing in the future in the new composite anechoic chamber, and integrated the latest test equipment related to intelligent connected vehicles, including V2X and e-call communication. It simulates real-world intelligent connected test conditions, using multiple communication antennas to create a reproducible experimental environment.
For example, it has a special function for future network antenna performance testing. Like navigation, V2X, mobile communication, so that the performance of the on-board antenna can be comprehensively evaluated at the level of the whole vehicle.
Another example is a dynamic driving test environment consisting of an active dynamometer and 2 turntables. The test environment will enable us to simulate ADAS (Advanced Driver Assistance Systems) functions and future scenarios related to autonomous driving in a closed architecture.
All in all, BMW's EMC laboratory is well equipped to conduct EMC tests for the more advanced connected cars of the future. This includes EMC testing for higher-level intelligent driving such as L3 and L4 in the future.
4 times higher testing standards than the industry
Some people may ask: how to detect the invisible, intangible, colorless and odorless electromagnetic waves that are invisible, intangible, colorless and odorless in the test object of electromagnetic compatibility? Here, BMW's engineers give the electric foal a vivid analogy: "We sometimes compare EMC research and development work to elephants and ants. ”
Ants are small and difficult to detect, and the electromagnetic interference we described earlier is like finding an ant in a car, and it requires very sophisticated instruments and measurement accuracy to detect this very small electromagnetic interference and radiation. ”
Elephant means that when we conduct electromagnetic immunity tests, in order to evaluate the impact resistance of vehicle products, we will emit electromagnetic energy of the same intensity as elephants into the vehicle to test whether our products have the desired immunity! ”
BMW's philosophy is that even if the electromagnetic interference emitted by the vehicle is as small as an ant, although it will not affect the vehicle, it will be able to identify the problem through sophisticated instruments and various test items.
Not only that, but BMW also has to build an "elephant-like immune system" that can withstand electromagnetic interference as large as an elephant when external facilities emit it.
BMW's ultimate goal is to build a more powerful "electromagnetic immune system" for BMW's products.
To do this, in the opinion of BMW engineers, it is necessary to use the most rigorous and highest-intensity tests to accurately detect the slightest electromagnetic interference and radiation.
Therefore, the electromagnetic test field strength specified in the industry standard is 30 volt meters, while the test field strength of BMW EMC laboratory can reach 100 volts on average, and the maximum test level is up to 140 volts under the limit test state, which is 4-5 times of the domestic legal standard and much higher than the industry standard.
In addition, BMW's test range covers from low to high frequencies, as well as different operating conditions. For example, during the test, BMW will cover the frequency of 100kHz-6GHz, which is also the interference range of most electronic components in the car. In some cases, even the consideration of the potential interference of electric vehicles with respect to the human body has been incorporated.
In this way, by fully simulating the various electromagnetic interferences that the vehicle can receive when driving on social roads, a strong "immune system" can be built for BMW vehicles.
Summary of the electric foal
BMW's understanding and interpretation of luxury is not only in the design, materials, and configuration, which we can see, but also in more invisible luxury.
For example, in order to bring users a more stable and secure intelligent experience, BMW has established the industry's most leading EMC electromagnetic compatibility laboratory, and will also undergo the industry's most stringent EMC electromagnetic compatibility test, giving BMW the most powerful "electromagnetic immune system".
There are many other unseen luxuries like this at BMW, such as "purgatory" safety tests with no upper limits, just to ensure that the vehicles delivered to Chinese customers are safe and reliable. Another example is the L2+ level intelligent driving assistance system test with a mileage of more than 130,000 kilometers, just to create an intelligent driving system that is more in line with China's road conditions and ensure that Chinese users can use the function safely and conveniently.
As BMW engineers said: "The place that consumers can see is the hardware design and engineering design, but there are many invisible places, such as software design, BMW's unique tuning, and integration capabilities." These visible and invisible, for BMW, luxury is by no means a pile of materials and book data. ”