AutoBeta(AutoBeta.net)05/29 Report--

Recently, Great Wall Automobile publicly reported that two BYD models use atmospheric fuel tanks, suspected of substandard evaporative pollutant emissions from the vehicle, causing heated discussion among the majority of netizens.

Today, BYD responded again on the investor interactive platform that the atmospheric fuel tank steam emission control technology independently developed by BYD can achieve evaporative emission standards. It points out that BYD DM-i is a series-parallel structure of two motors based on the electric vehicle platform, which can decouple the engine from the wheel (detach the connection), the engine can start flexibly in EV mode, and the fuel steam can be desorbed freely (oil and steam can be removed from the carbon tank). At the same time, coupled with the cooperative strategy of multiple control units and the in-depth study of the characteristics of the carbon tank, the fuel steam emission control technology of the atmospheric fuel tank is developed. This technology can realize that the PHEV will start the engine automatically before the carbon tank is saturated, even if the vehicle is used in EV mode for a long time, and the problem can be solved in about 4 minutes without increasing fuel consumption or noise. It can also complete fuel steam desorption, vehicle power generation and engine maintenance, which is both reasonable and legal.

In addition, BYD also explained through an example that the atmospheric fuel tank of BYD's PHEV model can also meet the emission regulations. Take the Shenzhen area as an example, when the vehicle is parked, the fuel tank can produce 3-5 grams of oil vapor every day. Under EV condition, about 1 gram of oil vapor can be produced for every 100km driving, and the oil vapor produced is absorbed by the carbon tank. On average, the weight of the carbon tank increases by 46.6 grams a day. If the average value is 5 g / day, the weight of the carbon tank will increase by 30 g after 6 days. Taking BYD 1.5L self-priming engine as an example, the desorption capacity of 40g to 50g can be achieved in about 4 minutes, which can ensure evaporative emission compliance.

According to a related incident review, Great Wall issued an official statement on May 25, saying that on April 11, it had submitted reporting materials to the Ministry of Ecology and Environment, the State Administration of Market Supervision and Administration, and the Ministry of Industry and Information Technology, reporting on the substandard emission of evaporative pollutants from the vehicle suspected of using atmospheric fuel tanks for Biadiqin PLUS DM-i (product model: BYD7152WT6HEVC2) and Song PLUS DM-i (product model BYD6470ST6HEV2).

In response to the report of Great Wall Motor, BYD also quickly issued a statement saying that it firmly opposes any form of unfair competition and reserves the right of legal action. In the case mentioned by the Great Wall, the test vehicles were purchased, kept and arranged for inspection by the Great Wall, and the China Automobile Center (Tianjin) tested the relevant projects in accordance with the requirements of the Great Wall. Strictly speaking, the inspection status of the test vehicle that does not meet the requirements of the national standard, that is, it should be sampled, kept and submitted for inspection by a third party, and it is required to complete the test after running-in of 3000 km, while the mileage of the vehicle submitted for inspection of the Great Wall is only 450km to 670km. In view of the above, BYD believes that its test report is invalid, and Great Wall cannot be used as a basis.

The report by Great Wall that BYD is suspected of substandard evaporative emissions has also sparked heated debate among other car bosses, saying that their models use high-pressure fuel tanks. For example, the ideal automobile CEO said: the high-pressure fuel tank of the ideal ONE was developed by a Korean enterprise, and at that time there was no domestic supplier to develop the high-pressure fuel tank. At that time, many experts did not understand why the metal high-pressure fuel tank was used and was hacked for a long time. There is also a zero-running car COO also commented on Weibo: in the barbaric growth environment to stick to the original mind, build the car that users need. Because the owners of C11 extended range use pure electricity mode for a long time, the high pressure fuel tank with maximum pressure capacity up to 35kPa has been selected at the beginning of the product design, and can meet the national 6b emission standard under all operating conditions.

It is worth noting that BYD also answered other relevant questions raised by investors one by one. For example, what are the technical routes for BYD PHEV plug-in hybrid to solve the problem of meeting steam emission standards? BYD said that at present, there are two main technical routes of PHEV plug-in hybrid in the industry, one is based on fuel vehicle platform development, motor and power system superposition, can not achieve engine and wheel decoupling (disconnection), EV mode engine can not flexibly start for desorption (extraction of oil and steam from carbon tanks), so must be equipped with high-pressure fuel tank to meet evaporative emissions regulations. The other is the series-parallel structure of double motors based on the electric vehicle platform, which realizes the decoupling between the engine and the wheels. In EV mode, the engine can start flexibly for desorption, so the atmospheric fuel tank can also meet the requirements of evaporative emissions regulations.

With regard to the rumors that BYD's PHEV plug-in models adopt different solutions at home and abroad, the official also responded that BYD has accumulated more than 20 years of PHEV plug-in hybrid technology, has a strong independent research and development capability, atmospheric fuel tank technology solutions, but also high-pressure fuel tank technology solutions. In application, both at home and abroad, atmospheric fuel tank and high pressure fuel tank are adopted, which are in line with the local evaporative emission regulations and standards.

It is understood that the automobile fuel tank is generally divided into atmospheric fuel tank and high pressure fuel tank. When the fuel vapor pressure in the atmospheric tank reaches 4~7kPa, the fuel steam valve located on the fuel tank opens and the fuel vapor will be released into the carbon tank. High-pressure fuel tank can generally withstand higher steam pressure, up to 35-40kPa steam pressure, oil will remain in the fuel tank under high pressure, until the engine running through the carbon tank into the manifold, can better collect volatile oil and gas in the fuel tank while the vehicle is running, effectively reduce fuel evaporation loss and environmental pollution. Some relevant professionals have pointed out that if the plug-in hybrid (that is, plug-in hybrid) does not use fuel for a long time, there will be too much evaporation, carbon tanks can not be absorbed, and other problems, which have higher requirements for fuel tanks. if you use a high-pressure fuel tank, you can reduce evaporation emissions.

Welcome to subscribe to the WeChat public account "Automotive Industry Focus" to get the first-hand insider information on the automotive industry and talk about things in the automotive circle. Welcome to break the news! WeChat ID autoWechat