Shulou(Shulou.com)11/24 Report--

Great Wall Motor issued a statement on May 25, reporting that BYD Qin PLUS DM-i and Song PLUS DM-i were suspected of substandard evaporative pollutant emissions from their vehicles using atmospheric fuel tanks.

Subsequently, BYD issued an official statement in response that it "firmly opposes any form of unfair competition and reserves the right to legal proceedings."

As we all know, gasoline is a kind of industrial oil that is easy to evaporate, and plug-in hybrid cars have a large capacity of battery pack, which can achieve pure electric life of hundreds of kilometers, so a large part of users will drive mainly with pure electricity. If you use more electricity, the engine will intervene less, and even will not start for a long time. But at this time, the gasoline steam in the fuel tank will still gradually accumulate. After reaching a certain degree of saturation, part of the gasoline steam will be discharged directly into the atmosphere, causing air pollution.

Therefore, many mixed models will choose "high-pressure fuel tank", "high-pressure fuel tank" can withstand greater pressure of gasoline steam, thus reducing the possibility of gasoline steam being discharged into the atmosphere.

The report statement of the Great Wall focuses on the key word "high-pressure fuel tank", believing that BYD Qin PLUS DM-i and Song PLUS DM-i use atmospheric fuel tanks, which are suspected of substandard evaporative pollutants from the whole vehicle.

In its response, BYD stressed that "strictly speaking, the inspection status of the test vehicle does not meet the requirements of the national standard, and that the test report is invalid, and the Great Wall cannot be used as a basis."

At the same time, BYD stressed that "as the first company in the world to launch plug-in hybrid vehicle products, BYD has more than 20 years of accumulation and iteration in plug-in technology, which is not as simple as some peers think." and said that the products and related testing meet national standards and have passed certification in national authorities. Relevant departments are welcome to come to investigate, collect evidence and test at any time.

Two giant car companies "fight", in the end is not up to the emission standard or unfair competition? We can't draw a conclusion here, but the recent disclosure of a BYD hybrid patent information seems to explain the problem of "atmospheric fuel tank" to some extent.

It is understood that the application date for this invention patent is June 18, 2020, and the name of the invention patent is "control methods, control devices and hybrid vehicles for hybrid vehicles".

It is shown that when the vehicle is in electric mode, the carbon tank adsorption capacity is determined according to the pre-established carbon tank adsorption model; and when the carbon tank adsorption capacity is greater than the preset value, the electric mode is switched to a hybrid mode for carbon tank desorption.

Through the technical proposal provided by the invention, the adsorption capacity of the carbon tank can be estimated when the engine is not started without increasing the hardware cost such as spare parts, and the operation mode of the vehicle can be automatically switched to the hybrid mode before the carbon tank tends to be saturated, so as to desorb the carbon tank in time, so as to effectively avoid the occurrence of fuel steam leakage caused by carbon tank overload. Ensure that the carbon canister can work effectively for a long time.

To put it simply, this invention patent solves the problem that hybrid cars meet national pollutant emission standards without high-pressure fuel tanks.

This background technology is to reduce the evaporative emission of the engine fuel evaporation system. The oil and gas recovery system generally absorbs oil and gas through the carbon tank, desorbs the oil and gas in the carbon tank by using the vacuum of the engine intake manifold, and introduces it into the engine fuel. to achieve the purpose of cyclic adsorption and desorption of oil and gas. However, the electric mode accounts for a large proportion in the daily driving process of hybrid electric vehicles, so there are some problems such as short engine running time, less opportunities for carbon tank flushing and insufficient oil and gas desorption capacity. The engine of the traditional gasoline vehicle is in the running mode for a long time, so the oil and gas adsorbed by the carbon tank can be desorbed in time, while the running time of the engine of the hybrid vehicle is too short, the oil and gas adsorbed by the carbon tank can not be desorbed in time, so it is easy to overload the carbon tank.

In order to meet the requirements of national standards and reduce the emissions of hybrid electric vehicles in the actual use of vehicles, there are two solutions.

The first scheme is to enhance the oil and gas adsorption capacity by expanding the capacity of carbon tanks, and the second scheme is to use NICRO (Non-Integrated Refueling Canister Only, non-integral control only refueling carbon tank system) evaporative emission system. BYD believes that the first scheme has certain limitations in terms of performance-to-price ratio and feasibility, while the second scheme increases a lot of spare parts costs, and the structure is more complicated, and the performance-to-price ratio is low.

To this end, BYD's invention patent gives a new method:

When the vehicle is in the electric mode, the carbon tank adsorption capacity is determined according to the pre-established carbon tank adsorption model; and when the carbon tank adsorption capacity is greater than the preset value, the electric mode is switched to a hybrid mode for carbon tank desorption.

And there are a series of optional inventions, including the determination of diurnal adsorption capacity according to the day-to-day ambient average temperature, the diurnal temperature difference, the fuel tank fuel level and the number of days between electricity on the vehicle, including: determining the daily single diurnal adsorption capacity according to the daily daily ambient average temperature, the diurnal temperature difference and the fuel tank oil level; and determining the diurnal adsorption amount according to the daily single diurnal adsorption amount.

When the vehicle is in a non-electric mode, the carbon tank load is determined according to the pre-established carbon tank load model, and the day and night adsorption capacity calculated in the carbon tank adsorption model is modified on the basis of the carbon tank load.

The current publication date of the patent application is December 2021, and judging from the content, it seems that BYD stressed in its response that the relevant departments should come to investigate, collect evidence and test at any time.

In addition, according to network information, BYD DM-i solved the technical problem of free desorption of gasoline steam from PHEV atmospheric fuel tank, achieving "one static and three gains": one static, excellent NVH, gasoline steam desorption can be achieved without induction and quickly while driving; third, fast desorption, efficient power generation and engine maintenance can be realized. And in a long time EV driving, about 6 days will start the engine for a short time, while generating electricity, lubrication and desorption.

A year ago, BYD officially announced that it would stop fuel vehicle production and focus on new energy business, becoming the first car company to stop producing fuel vehicles. And in April this year, BYD ushered in another historic moment in its development history-- the amount of risks on the terminal showed that the cumulative risk of BYD passenger cars exceeded that of FAW-Volkswagen and SAIC-Volkswagen combined in the first quarter of 2023, officially ranking first in China's auto sales brand. This is also the first time that this goal has been achieved by independent brands in the nearly 40-year history of the development of passenger cars in China.

Some netizens think that BYD is a "big tree to attract wind", in the face of booming sales, competitors are anxious. There are also netizens who think that the dispute between the two sides is good for the development of the industry and consumers. What do you think of it? CTOnews.com will also keep an eye on this incident.

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