A few days ago, the reporter learned from an industry expert familiar with the formulation of motor vehicle pollutant emission standards that in March this year, the mainland's next stage of motor vehicle emission standards opened the third phase of pre-research, which also means that the formulation of automobile pollutant emission limits and measurement methods (China's seventh stage) (hereinafter referred to as the seventh) was officially launched. On November 30, 2023, the State Council issued a notice on the issuance of the Action Plan for Continuous Improvement of Air Quality, which clearly stated that "research and formulate the next stage of motor vehicle emission standards". According to public information, the Ministry of Ecology and Environment's Motor Vehicle Emission Monitoring Center has led the first phase of the national seventh-stage pre-study of the national seven-stage motor vehicle pollutant emission standards in October 2020, and the second phase of the pre-study will be carried out in September 2022 and completed in December 2023. The China VII emission standard is about to be released.
PN limits are revisited
"According to my personal estimates, after a relatively long preparation process, it is expected that a draft for comments may be issued in 2025 to solicit opinions from the society and the public, and according to past experience, the formal standard document will be officially released in 2026. The above-mentioned industry expert said, "From my point of view, combined with the problems in the implementation of previous emission standards, I feel obligated and responsible to call on industry enterprises to pay attention to some possible new changes in China VII and avoid a passive situation after the introduction of new regulations." ”
In fact, in the implementation of the National VI emission standards, the steps and rhythm of the promotion have brought great challenges to the industry - in addition to distinguishing between light vehicles and heavy-duty diesel vehicles, according to the "Three-year Action Plan for Winning the Blue Sky Defense War", including Beijing-Tianjin-Hebei and its surroundings, the Yangtze River Delta, the Pearl River Delta region, etc., including the key areas in the rhythm of the implementation in advance, and then the number of particulate matter (PN limit) of the China VI emission standards for light vehicles has made waves again. On May 14, 2020, the Ministry of Ecology and Environment, the Ministry of Industry and Information Technology, the Ministry of Commerce, and the General Administration of Customs jointly issued the Announcement on Adjusting the Relevant Requirements for the Implementation of the National VI Emission Standards for Light Vehicles, adjusting the transition period for the PN limit.
According to the reporter, the first introduction of PN limits in the mainland emission standards was when the National VI emission standards were implemented, and the understanding and preparation of particulate matter emissions in the industry at that time was not profound. Combined with some of the impacts of the new crown epidemic at that time, objectively, the industry's preparedness was insufficient to a certain extent.
From the sharing of industry experts, we can get a glimpse of the requirements for PN limits in the formulation process of China VII in the future, and there is a considerable probability that they will be further tightened. Taking history as a mirror, industry enterprises need to start early, pre-research in advance, choose a reasonable and reliable technical route, and make reserves.
The stones of other mountains can be used to attack jade
From a top-level perspective, in September 2015, "insisting that lucid waters and lush mountains are invaluable assets" has been written into the central document ("Opinions on Accelerating the Construction of Ecological Civilization"), and then the 19th National Congress of the Communist Party of China also wrote the "Two Mountains Theory" into the "Constitution of the Communist Party of China". Controlling the impact of motor vehicle pollutants on the atmosphere has become a must for the entire automotive industry. Controlling the amount of particulate matter emitted by motor vehicles is conducive to further protecting our green waters and blue skies, and has also become the responsibility of the automotive industry. From the perspective of national standards, the tightening of PN limit indicators is reasonable and inevitable under the guidance of the general policy of building ecological civilization.
From these dimensions, improving the understanding of technical indicators of PN limits may become a compulsory course for vehicle and supply chain enterprises.
Our country's emission standards have been learning, learning from and benchmarking European emission regulations for a long time, so with reference to the requirements of the Euro VII standard for PN limits, we can roughly predict the direction and scope of the China VII standards (about PN limits).
The reporter combed through the public information and showed that the Euro 7 standard has gone through a relatively long preparation and complex game process from planning and formulation. The EU once hoped to use Euro VII to reshape the EU's pioneering and leading image in the field of zero pollution and carbon emission reduction in the world. After a series of subsequent changes in the geopolitical situation and economic environment, the attitude of EU countries towards the Euro VII standard is somewhat delicate, and after many rounds of communication, coordination and game by the European Commission, the EU Council and the EU Parliament, there are certain compromises and compromises in the Euro VII standard. For the PN limit, Euro VII retains PN10 instead of PN23, removing the scope limit of the PN limit, and RDE continues to maintain the EU6e standard, with its compliance factor coefficient between 1.1 and 1.34. If we benchmark Euro VII, the continent's current emission standards are already ahead of the EU in terms of indicators.
"My personal estimate is that in the formulation of the seventh country, the mainland will adopt a more prudent and moderate evolutionary approach. At the same time, Euro 7 also gave several important enlightenments to mainland industry enterprises. Expert analysis pointed out, "the first revelation is that the PN limit index will be tightened with a high probability, but the form of tightening is not necessarily the change in the number of particles, but the adjustment of the diameter standard of particles, small particle size particles are included in the test, supervision, so as to actually become more stringent; ”
Loading GPF to grab RDE Both hands should be hard
With the vigorous development of the automotive industry in Continental, Continental's automotive products are becoming more and more abundant, especially in the wave of electrification, Continental's automotive market has gathered almost all powertrain technology routes and configurations. On the one hand, this is a strong symbol of our automobile industry, and at the same time, this situation (different technical routes and power configurations meet the national VII emission standards) has also brought considerable difficulty and complexity to the research and development work of enterprises.
"We are very concerned about the PN limit of China VII and the relevant content trends of RDE testing. Although we had a hunch that the task would be daunting, we had already started early follow-up research within our team. In principle, particulate emissions are generated mainly due to the formation of a liquid oil film (liquid oil film due to insufficient combustion) formed during the injection of fuel (gasoline). However, these liquid oil films are easy to exist in the piston top and cylinder wall in the cylinder, forming particulate emissions. At the same time, it is closely related to the ambient temperature. When the ambient temperature is lower and the chiller is started, the fuel vaporization is not sufficient, and there is more liquid oil film, which will also produce more particulate emissions. Li Shunqing (pseudonym), associate professor of the team, said Li Shunqing (pseudonym), an associate professor at a key university in China, "so from our design perspective, we will focus our research direction on taking targeted solutions in combustion development." For example, we try to optimize the angle of the fuel injection beam so that the oil beam does not hit the valve and cylinder wall as much as possible, we pay attention to the injection pressure, which reduces the fuel particle size but also increases the penetration distance, so we need to balance, and we also try to use a multi-injection scheme to reduce the possibility of oil droplets hitting the cylinder wall. At the same time, due to the existence of a variety of hybrid configurations in domestic vehicle enterprises, we also recommend that the internal combustion engine and motor be jointly debugged and standardized, and the idea is to make the engine work in the hot engine state as smoothly and stably as possible, especially to avoid the instantaneous and violent fluctuation of engine load under the cold engine condition. ”
In many interviews with reporters, many people in the industry realized the importance of particle capture device (GPF) in the seventh stage of China. From the perspective of the technical solutions of international brands in Europe, since the Euro VI stage, most brands have adopted particle capture devices to meet the requirements of EU emission regulations for PN limits. The particle capture device has a very obvious effect in coping with the fluctuation of particulate matter emissions caused by the switching of engine cold and hot engines, sudden changes in engine load, and changes in fuel quality. If the optimization of the design angle is to practice the "internal force", the application of the particle capture device is to add an "external plug-in" to the emission control. According to the reporter's understanding, according to the current technical level, the filtration efficiency of GPF products can reach 90%, and the next generation technology is even expected to exceed 95%.
Particle capture devices are also very helpful for various hybrid configurations. Relevant research data show that the route represented by non-plug-in hybrid power is difficult to rely on design to reduce particulate matter emissions to meet PN limit requirements, and the assistance of GPF has become a must. In the configuration of the series-parallel plug-in hybrid design, the cold engine performance of the internal combustion engine is greatly affected by the strategy of the motor and engine controller, which helps to further control the emission level with the assistance of GPF.
In addition to the design perspective, it is recommended that vehicle and supply chain companies pay attention to the relevant trends of RDE testing. Compared to the China VI emission standard, the RDE test of China VII will include the emissions from the cold start phase in the formal accounting. If the China VII standard strengthens the verification of low temperature environment and cold engine start-up in the certification and random inspection, then GPF may be the most cost-effective solution.
Text: Ma Xin Editor/Layout: Zhao Fangting
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