Last time, Brother Neck had already questioned everyone about the Jie M7 catching fire in a rear-end collision.
In the comment area of the article, in addition to AEB, everyone is also concerned about the problem of hidden door handles popping up. Because it can be seen from the video of the collision that the hidden door handle of the Wenjie M7 never popped out during the collision.
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Many netizens suspected that it was precisely for this reason that neither the kind-hearted passers-by who came to help nor the rescuers who came later could open the door. In the end, they had to find a way to smash the window, wasting rescue time.
According to our simple understanding, after a collision, the vehicle will usually automatically unlock, and at the same time as it is unlocked, the door handle should pop out.
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But the reason why the door handle didn't pop out is really unclear.
Some bloggers said that the collision speed was as high as 115 kilometers per hour. The sprinkler truck invaded the cockpit in less than one second and cut off the power cord. As a result, the car failed to flash, causing the door handle to pop up and other functions. All failed.
In addition, we do not rule out the possibility that the door handle may be stuck by the car door, or the small battery may be damaged, causing the emergency mechanism to fail. In short, it is currently impossible to draw a conclusion as to what went wrong in this accident.
We still have to wait for the authoritative announcement from the police to know what the situation is.
But no matter what, the hidden door handle is the one that has to take the pot.
Many netizens say that if you use traditional mechanical door handles, there won't be so many problems.
This statement actually makes sense.
Because previous mechanical door handles were all exposed designs, at least there was a handle that could be pulled, and the door opening was fully mechanical and did not require electricity at all.
The hidden door handle is different. You have to make it pop up before the user can open the door, right?
Regarding this “pop-up” mechanism, different car companies have different design ideas. Generally speaking, they are usually divided into two types: rotary type and flat push type.
Some early trams basically used rotary ones, such as the Xpeng P7. After the door is unlocked, the door handle will automatically rotate and pop up.
But if we say that this method is unsafe, we would be wrong to blame it.
Because rotary door handles do not encounter the problem of being stuck and unable to open the door. In addition to electric control, they generally retain the manual pressing method. Even if they do not pop out by themselves, you can press them from the other side and they can come out. .
Tesla Edamame 3 owners have the most to say about this function. After all, it won’t pop up at all, but like a lever, you need to press one side to make the other side tilt up. It can be said that it is a mechanical door handle. .
Another kind of flat push door handle is more likely to cause the car door to fail to open.
Because it has no other physical way to pop out, if the car doesn't rely on a motor to push the door handle out, you can't open it outside.
If you want to dig it out, it's not impossible, but if you encounter a life-threatening moment, by the time you dig it out, it might be too late.
And generally speaking, the sliding door handle structure is more complex and takes up more space. So in terms of actual use, it is indeed relatively easy to break.
The picture below is a typical push-type door handle structure. It is based on the traditional door handle and adds a handle opening drive motor and two capacitor position signal switches.
Because the door handle is all embedded inside the door, its layout will take up more space in the door, and some collisions and extrusions may cause the ejection channel to be blocked.
Moreover, the push-type door handle must retain the pop-up mechanism, which requires an additional motor and corresponding circuits. In addition to the possibility of poor contact and electronic system failure, there have also been cases of gear lubricant leakage and dry-explosion of the door handle motor.
Although car companies have optimized production materials and processes, such as precision control of sheet metal parts, development of special nut adjusters, etc., flat push door handles are still a safety hazard.
Moreover, there are currently no relevant national standards for this type of door handles, so it’s hard to say how much safety redundancy car companies can achieve in this matter.
Some car companies will arrange for you to automatically pull down the window within 15 seconds after a collision, but it still needs to be powered by a 12V small battery. Some car companies will also set up a separate small backup battery in the door to specifically control the door opening.
But in order to make the hidden door handle look cool, countless patches were put on it. Let me tell you, it’s better to just do it. . .
However, before considering how to open the door, there is actually a prerequisite.
We have to ask first, are the car doors unlocked?
Otherwise, even if you use a mechanical door handle, or if you pull out the hidden door handle, you still won't be able to open the door.
For example, in the accident like Wenjie, did the M7 automatically unlock the doors?
Wenjie customer service responded this way, saying that most vehicles currently do not have the automatic unlocking function. In the event of an accident, even if you pull the door handle out, you still can't open it.
If you want to open the door, there is only one way to open it from the inside, but the passengers are unconscious at this time, so everyone can only smash the windows.
But this statement from customer service is untenable.
The national standard GB20071 “Occupant protection in side collisions of automobiles” has clear requirements, saying that after a collision, the door should be closed and not locked. In other words, it must be automatically unlocked.
In the 2021 version of C-NCAP (China New Car Assessment Program), the requirement that the door must be actively unlocked after a frontal collision has also been added. Without this function, 1 point will be deducted from the crash test score.
At the same time, the Ministry of Industry and Information Technology's “Rear Collision Safety Requirements for Passenger Cars” (draft for comments) at the beginning of this year actually mentioned that “after the collision test, the door should be in an unlocked state,” indicating that this matter is a recognized standard in the industry.
As a car, you have to abide by the national standards, right?
Later, netizens dug out the owner's manual of the M7, which clearly stated that it does have an automatic unlocking function.
But even so, the automatic unlocking function does not mean that the door will be 100% unlocked after a collision.
Fundamentally speaking, automatic unlocking is a relatively basic configuration, which mainly involves two modules, one is ACU (Airbag Control Module) and the other is BCM (Body Control Module).
As you can tell from the name alone, the ACU is bundled with the airbag, while the BCM is responsible for controlling various functions of the body.
Its principle is that after the car's collision sensor detects that your car has crashed, the ACU will be responsible for opening the airbag and giving an electrical signal to the BCM at the same time. At this time, the BCM will control the door unlocking.
For example, this ACU is like the BCM's little secretary. It first collects feedback from various departments, solves some of it by itself, and then reports to the leader BCM to handle less urgent matters such as unlocking the car door.
If the ACU, BCM, or even the intermediate transmission wiring harness is damaged in a collision, there is a certain chance that the door cannot be unlocked.
Moreover, this system requires electricity just like the hidden door handle. After a collision, the power battery will be directly powered off. All functions in the car rely on the 12V small battery to continue their life.
If at this time, the small battery is damaged and the door cannot be unlocked automatically.
For example, in July 2022, there was a similar incident. A Lexus LM crashed and burned, and the door could not be opened, resulting in 1 death and 2 injuries. This car still had a traditional door handle, so you still had to knock on the window to get in and save people.
Therefore, we cannot conclude that the reason why the car door cannot be opened is due to the hidden door handle.
But no matter what, if you use a traditional mechanical door handle, it will still be easier to open when the vehicle is unlocked and the door is not deformed or stuck.
This is actually the biggest flaw of the hidden door handle. Even if the vehicle is unlocked, but the hidden door handle does not pop out for you, there is still no place for people outside to open the door.
Even if the vehicle is locked, it will still delay the rescue of outsiders, especially the untrained enthusiastic people. Seeing that the door handle does not pop up and the window does not lower, it is really impossible to open the door.
Therefore, the core problem is to solve the process of unlocking the door after a collision, or make the hidden door handle optional. Anyway, I really don’t like this thing.