The hottest incident in the recent automotive circle is the BYD atmospheric pressure fuel tank incident, Great Wall Motor sued BYD's Qin PLUS DM-i and Song PLUS DM-i for using atmospheric pressure fuel tanks, suspected of the vehicle evaporating pollutants not up to standard, and said that it had submitted reporting materials to relevant departments.
BYD also made a strong response, issuing a document saying that the company's products and related testing meet national standards, and is even willing to share the control strategy and principle of core technology and patent results free of charge with all automotive peers.
For a time, these two independent car companies that once loved each other stood on opposite sides. At the same time, the fuel tank problem, which has always been ignored by consumers, has instantly become the focus of all. Presumably, many people also want to understand what is the relationship between atmospheric pressure fuel tanks and evaporation emissions? Why is there no concept of atmospheric pressure fuel tank in the era of fuel vehicles? In the new energy era, so much attention is paid to the structure of fuel tanks?
Atmospheric fuel tank is really bad
In fact, atmospheric pressure tanks have long existed, but on the fuel body, the gasoline vapor of atmospheric pressure tanks will not be emitted to the air and will not cause environmental pollution, so everyone does not care. Nowadays, atmospheric pressure fuel tanks have attracted the attention of manufacturers, because the times have changed, in theory, atmospheric pressure fuel tanks are not suitable for loading on plug-in hybrid models.
As long as we understand the working principle of the fuel tank, we will understand the limitations of the atmospheric pressure tank. As we all know, gasoline has a strong volatility, if volatilized into the air, it will cause a lot of pollution to the environment, so the vehicle uses a carbon canister, using the adsorption of activated carbon to absorb gasoline vapor. These adsorbed gasoline vapors will be directed to the intake manifold of the engine, where they will be burned together with the gasoline to participate in the work of the engine.
That is, if a car burns oil frequently, then the gasoline vapor in the tank will be continuously absorbed by the carbon canister and constantly burned, and the steam in the tank will not accumulate.
But when it comes to hybrid models, everything has changed. The current hybrid model is in a pure electric state, and the range is 100km or 200km at every turn, so everyone can use the car directly, and the gasoline in the fuel tank is in a "static" state for a long time. And these unused gasoline, through continuous volatilization, will accumulate a large amount of gas in the tank.
In the long run, the fuel vapor adsorbed by the carbon tank in the tank will reach a saturated state, in this case, if it is an atmospheric pressure tank, then the gasoline vapor will overflow the fuel tank, thereby polluting the environment, which is the root cause of Great Wall Motor's report on BYD.
High-pressure fuel tanks aren't necessarily perfect either
Because the atmospheric pressure tank is subjected to limited steam pressure of the car, only 3.5-4.0K· Pa, so Great Wall Motor believes that it is not suitable for hybrid models, but should be equipped with high-pressure fuel tanks, and their pressure-bearing capacity reaches 35-40K· Pa, which is ten times that of atmospheric pressure tanks, so high-pressure tanks can carry more gasoline vapor, which is especially important for hybrid models.
From this point of view, the hybrid model is of course better to use a high-pressure fuel tank, even if the vehicle has been running on electricity, the fuel tank can store all the steam inside the tank. However, the high-pressure fuel tank with stronger performance is also higher in terms of manufacturing cost, about a thousand yuan higher than the atmospheric pressure fuel tank, so after BYD's model was exposed to the use of atmospheric pressure fuel tank, the outside world thought that it was cutting corners.
Indeed, it is not advisable for car companies to cut corners, but the question is, does the use of atmospheric pressure fuel tanks mean that car companies cut corners? Speaking of this, car buyers remembered the current hot range extension technology, once the range extension technology was also regarded as a backward product, but after years of technological improvement, it can now also adapt to the development of the new energy era, and even bring a better car experience.
Atmospheric pressure fuel tank is the same reason, BYD said that the atmospheric pressure fuel tank of its model incorporates more new technologies independently developed by BYD, so the problem of atmospheric pressure fuel tank applied to plug-in hybrid models has been effectively solved, and this solution is mainly to occasionally start the engine and burn the gasoline vapor in the tank.
As for boring new technologies, buy a car without further talking, let's take a look at the specific performance of the vehicle. According to the information released by BYD, when the Qin PLUS DM-i and Song PLUS DM-i are working in the EV state, if the vehicle encounters sharp acceleration, high speed, climbing, high temperature, low temperature, low power, engine maintenance needs, etc., the engine will intervene and automatically turn on the HEV mode. It is at this time that the user is forced to turn on the EV mode, and certain conditions are also required. In other words, when the vehicle needs a stronger power output, the engine will naturally start, helping the motor to drive the vehicle forward.
In fact, the working principle of BYD DM-i is not difficult to understand, if you have driven plug-in hybrid models, then they can not always maintain a pure electric state, such as accelerating overtaking, and climbing the need for stronger power output, as long as you step on the accelerator a little deeply, the engine will automatically intervene, then the gasoline and gasoline vapor in the tank will be burned, and there will be no problem of excessive steam volume.
It is worth mentioning that because of its own technical hardcore, on May 29, BYD also publicly expressed its willingness to share the control strategy and principle of core technology and patent results with all automotive peers for free, while accepting the analysis and discussion of industry experts.
For the atmospheric pressure fuel tank, BYD did not avoid the problem, but admitted that the vehicle uses both atmospheric pressure fuel tank and high-pressure fuel tank, but both of them can meet the regulatory requirements by integrating their own technology. From this point of view, for hybrid models, the type of fuel tank is not the focus, and technology is the core game point. BYD has accumulated plug-in hybrid technology for more than ten years, and I believe that its technology will not be bad, but this does not mean that BYD's wording is completely trustworthy, and the final authoritative investigation results can give accurate answers to this fuel tank incident.