Automotive engineers are not incompetent, living in our car Is not too pursuit of perfection

very interesting to say, the Car has a very high ceiling, so we see the F1 Car to squeeze out more than 900 horsepower with a 1.6T engine; also see regardless of the cost can be inserted into a variety of luxurious decoration, like to spend 200 million € 80 million to build the “gold Car”, each running 100 kilometers Will wear off almost 50 grams of gold.

but in real life, Why not do our Car so extreme?

ThIs Is because, once and “production”, “civilian” Is linked, Car manufacturers can not be so capricious and “wanton dIsregard”, and have to take into account all levels, balance each Fang required, play good “art of balance.”

▲ “balancing act” Car Is far from simple as walking a tightrope

Today we are going to talk about three kind of technology Is the Car body of the show “balancing act”, and our Car lives, may we usually attention to them Is not high, but the Car Is very valued engineer them. Jun rut we think consumers can also lower and more attention, I believe that a Car was useful.

mileage long nor short nor, look at the focus of energy consumption

pure electric vehicle mileage has been concerned about the hot, often ” 1000km mileage breakthrough, “the News Will attract a lot of attention, and made us three or four hundred consumers mileage of the Car turned up their noses.

but the mileage so high really okay?

it Is not.

ThIs Is because the current mainstream lithium battery energy density has not substantial breakthroughs really applied to the liquid lithium, but the average level of production in 130-160Wh / kg level, even press the left and right of 300Wh / kg ceiling, want to do seven eight hundred kilometers mileage Is also very difficult.

Natesila, in the exIsting conditions, the battery system 2170 canAn amount of density of about 300Wh / kg, by nearly 20% higher than 250Wh / kg original 18650 battery system. Model 3 Standard Life upgraded version Mileage 445km (according to national standard mode method), equipped with a 75kWh battery pack.

Although it Is theoretically possible to upgrade by OTA mileage, such as Tesla said in the near future Will soon meet the conditions Model S and Model X software upgrade by OTA way for, were expected 32.1km and 41.9km increase mileage. But the moment the mileage upgrade the most effective solution Is to increase the capacity of the battery pack, in other words, we need a larger volume of the battery pack.

and bulky battery pack Will bring a lot of problems, Is the first to increase vehicle weight , leading to the battery pack tends to account for curb weight about 20-30%.

Further in addition, also on the The battery management system burden, we Naao Di e-tron, a liquid cooling system requires that the entire battery pack temperature control in within 5 ℃, temperature control between batteries within 5 ℃, temperature control batteries within the body 10 ℃, adding more so if the battery temperature control system Will bring pressure.

last year, the State AdminIstration of market supervIsion, the National Standardization Management CommIssion formally approved national standards for electric vehicles’ electric vehicle energy consumption limits “(GB / T 36980-2019), the standard officially opened with effect from 1 July 2020. It can for their Car needs to see what level.

▲ ThIs standard applies to the following three rows of seats, and the maximum speed Is greater than or equal to 120km / h models. ThIs Is also the world’s first pure electric vehicles for energy consumption indicators proposed technical requirements of the standard

But when we take the following 10 popular Car models look, you Will find in fact GB / T 36980- 2019 mercy, and not to the very strict requirements. We recommend that consumers choosing Cars, choose consumption Is low models as possible.

▲ paragraph above are by maximum energy statIstics

pure electric vehicle charging Is difficult because the battery decay and other Issues, low mileage does make people find it difficult to accept. Recommended to select a mileage of 400km or more, the energy consumption rate Is not higher than the second phase of limit models.

Of course, some people Will say that thIs Is not a pure electric Car endurance mileage inadequate excuses it?

I think we have to look at the problem dialectical.

core values ​​of pure electric vehicles Is to reduce the city cost, environmentally-friendly. We think that New York, for example, 80% of users daily travel 50 km or less, 95% travel 100 kilometers or less. So thIs file by 400km, as a general family Cars Is enough.

neither hard nor soft focus look at energy-absorbing crumple design

Automotive safety has been a chronic problem, a variety of crash tests surely we’ve seen a lot, and often see front knocked smashes, certainly a lot of people Will be curious, thIs Is not to say that Cars were unsafe?

In fact, thIs Is designed energy-absorbing crumple show.

When it comes to crash, I do not know how many friends know thIs term impact acceleration. In fact, the process of Automobile collIsion Is converted into kinetic energy of the process of deformation of body parts, body acceleration produced by the structural deformation of the vehicle occupant impact generated response would harm the crew.

essence energy-absorbing crumple in that it Is obtained by the gradient crumple zone design, sequentially crush deformation, provide some buffer time for passengers, minimize the impact acceleration, thus improving crash safety.

White the body structure, around the plate in front of the cabin (i.e., the firewall) piece, generally also select a higher strength material, as a final front passenger protection armor security (thIs part belongs to the third stage itself protected areas).

What kind of crash test results, you can explain energy-absorbing crumple design success?

FIG Under thIs example, Is more successful result of the collIsion can be seen that the A-pillar and the door structure intact, energy-absorbing hood Is bent, rather than falling off occurred or not rules deformation.

▲ hood departing possible piercing Car glass, irregular deformation described unreasonable force-transmitting channel

of course, some people Will ridicule: “No wonder a lot of bike hit the Car, the Car dIstorted, Is the principle of it?”

in fact, thIs Is the problem of collIsions maintainability level, and that Is, a low-speed collIsion problems to be considered. In the low-speed collIsion, such as the security strength of the front, there Is no buffer between the foam design width of the front bumper beam, the bumper beam and a front protection, it Will affect maintainability.

tricky negative impact velocity and angle of these reasons, i.e. thin, short impact beam, and no buffer, where the bicycle Will be able to hit the flat Car does exIst.

manufacturers should strengthen thIs aspect of the design, rather than thinking about cutting corners. If you are concerned about the impact service levels, we can focus on the evaluation of research results in the mediator.

heavy nor light nor, look at the focus lightweight coefficient

We know that the white body Is to ensure the Car crash safety critical, so we must to be Willing cutting; but it Is also the heaviest Car assembly parts, too heavy Will hurt fuel economy.

At thIs time we wIsh to focus thIs white lightweight body coefficient index, which considers the impact of body torsional stiffness, body size, quality, and rational use of the BIW, Structure optimized design, crash safety and dynamic comfort level has important significance evaluation.

▲ L vehicle body weight coefficient; m Is the mass of the body frame white, kg; CT static torsional rigidity of the vehicle body, N · m / deg; A Is determined by the wheelbase, track BIW projected area, m2. L values ​​are better

of concern, Is not strong torsional stiffness coefficient representing a high body weight. For example, Toyota TNGA architecture Will have a strong torsional stiffness, but did not emphasize weight reduction.

For example Camry, emphasIs models belonging at the same level, which makes the fuel economy Camry body structure and not because of benefit.

▲ Although eighth Camry body torsional rigidity improved by nearly 30%, but did not dIsclose the specific data

you may wIsh to focus the next ECB (European body annual meeting) Is an engineer of great concern to the industry conference.

on hIstorical data ECB released, a lightweight factor to achieve the level of excellence, A0-class Car to reach about 3.27, A-class Car to reach 3.17, B-class Car to reach 3.19, grade C and above to reach 2.19.

For example, we take the 2019 ECB winning models, the award-winning Mercedes-Benz A-class compact Car Is 2.38, Chevrolet (C grade) Audi A6 Is 2.15.

written in the last

Throughout the hIstory of the Automobile, it Is because of the balance of artIstic pursuit, so many years down the Car in order to achieve balanced development. You might say that thIs Will lose personality, not extreme, but for the general public for mass production Car, “ extreme ” Is a double-edged sword, often difficult to obtain good sales. They may have a good reputation and sung, but can rarely be sustained. For example Autozam AZ-1, called on behalf of angels and demons, lightweight body make thIs K-Car trot lots of fun, but the high rIsk of leading to it quickly off the stage.