It's time for the hottest new energy vehicles to b

2022-08-12
  • Detail

It is time for new energy vehicles to bid farewell to NEDC

data released by relevant departments show that by the end of 2018, the number of new energy vehicles in China has reached 2.61 million, including 2.11 million pure electric vehicles, and the driving range of mainstream electric passenger vehicles has reached more than 300 kilometers; As of January 2019, the number of electric vehicle charging infrastructure in China has reached 853000, and the proportion of vehicle piles is becoming more and more reasonable

these data show that the promotion scale, technical level and infrastructure construction of electric vehicles in China rose to a new height in 2018, and the problem of charging electric vehicles, which has plagued consumers for many years, has also been effectively alleviated. It is reasonable to say that the mileage anxiety disorder that has accompanied consumers for many years should also be eliminated, but surprisingly, since the implementation of the new subsidy policy last June, consumers' mileage anxiety has increased instead of decreased. The reason is that the national subsidy policy focuses on encouraging electric vehicles with long driving range, and the electric vehicles produced by manufacturers also respond to the announcement. The driving range is generally extended, but there is a big gap with the actual driving experience of consumers, which makes consumers feel "I'm afraid they can't get home"

it can be seen that the contradiction we face is that the actual experience of consumers is practical, and the product announcements of car companies and the driving range marked on the rear of cars are also tested in accordance with national standards. So, what's the problem

the mileage contradiction originates from the NEDC working condition method "applied" in 1989.

the reasons for the large gap between the announced driving mileage and the actual driving mileage of electric vehicles can be summarized as the following six points. First, the reading of automobile instrument is inconsistent with the actual driving range; Second, the power battery has attenuation problems; Third, there are limitations in the test conditions. The driving range announced by the product is tested at room temperature, but consumers' actual driving power consumption is different throughout the year, so the driving range is naturally different; Fourth, the driving range of the product announcement is tested without using air conditioning, and the power consumption will increase significantly when using air conditioning for cooling or heating. Figure 9 the utilization of high gloss black effect spray free materials in cars will also shorten the driving range of the corresponding vehicles; Fifth, there may be consistency differences between the vehicles submitted for inspection by the enterprise and the vehicles produced in batch; Sixth, the product announcement is tested according to the European NEDC working condition method, which is quite different from the actual road conditions in China

through careful analysis of these six reasons, it can be seen that, in addition to the two natural reasons of inaccurate odometer and power battery attenuation, the fundamental reason for the great difference between the announced driving range and the actual driving range is the European NEDC working condition test method "applied" in China in 1989

nedc was originally used to detect the exhaust emissions of fuel vehicles

nedc working condition method was originally used to detect the exhaust emissions of fuel vehicles. Including automobile gasoline and diesel, plastics, rubber, chemical fiber, coating, adhesives, etc. in 1989, in order to control the rapid increase of automobile exhaust emissions, China promulgated the emission standard of light vehicle exhaust pollutants (the current standard number is GB 14671), It is required to use the working condition method to detect the exhaust emissions of newly finalized vehicles and newly produced vehicles. The test method was formulated with reference to the emission regulations of the United Nations Economic Commission for Europe (ECE) (at that time, there were two popular words in the industry: apply the ECE working condition method, and × Standard equivalent to Euro × Standard), the main detection content is the residual amount of carbon monoxide, hydrocarbons, nitrogen oxides, carbon dioxide and other harmful substances in vehicle exhaust to judge whether the vehicle emission meets the standard

in 1999, the ECE working condition method was adjusted and some highway tests were added. At that time, the State Environmental Protection Administration also revised the emission standard of light vehicle exhaust pollutants. The revised standard was named gwpb-1 1999 emission standard of light vehicle pollutants. The standard greatly tightens the emission limit of light vehicles under working conditions, and also modifies the test method, which has been used until now. The familiar emission standards for light vehicles from country 1 to country 5 are tested according to this method

NEDC working condition method is increasingly not suitable for China's national conditions

NEDC working condition method is composed of two parts of test projects: urban operation cycle and suburban operation cycle. The urban cycle test consists of four small cycles of 195 seconds, including idling, starting, accelerating, deceleration and parking. The maximum speed is limited to 50km/h, and the average speed is 18.35km/h. The suburban cycle test time is 400 seconds, the maximum speed is limited to 120km/h, and the average speed is 62km/h. From these test items, it can be seen that this method is very different from the actual driving situation of vehicles in China

nedc working condition method has several serious problems. First, most of the test time is at a constant speed, which is inconsistent with the actual driving process of Chinese vehicles according to the "road map of energy saving and new energy vehicle technology" previously released by the Chinese society of automotive engineering, and cannot reflect the actual energy consumption and driving situation of vehicles. Second, the test time is short and the driving mileage is short. The whole process is less than 20 minutes, with a total of 11.007 kilometers. It is impossible to test the characteristic parameters of the vehicle under different operating conditions in detail. Third, the impact of environmental temperature changes on vehicle operation is not considered, and the test at normal temperature (ambient temperature 20 ℃ ~30 ℃) is used to replace the four seasons of spring, summer, autumn and winter. Without air conditioning, electric heating and other restrictions, mileage errors are caused. Fourth, it is unable to accurately evaluate the energy-saving effect of new energy vehicles, which is not suitable for evaluating new technologies such as braking energy recovery, idle start and stop. According to the actual test of China Automotive Technology Research Center, under the current working conditions, the maximum gap between the actual fuel consumption and the theoretical fuel consumption of vehicles reaches 30%. It is not surprising that such a large difference causes consumers to question the accuracy, rationality and authority of the announced data

at the beginning, when China's automobile industry was backward and there was no basis for its own automobile working condition detection standard, the introduction or application of NEDC working condition method for detection did indeed promote the progress of China's automobile energy conservation and emission technology. However, the European working condition law is formulated according to the "European conditions". Over the past 30 years, with the rapid development of China's automobile industry and transportation infrastructure, the gap between the "European conditions" and China's national conditions is rapidly expanding

the more embarrassing problem is that China introduced NEDC working condition method at the beginning to test the emission level of traditional fuel vehicles, but now it is used to test the driving range of electric vehicles without exhaust emissions, which seems to be a bit of a donkey's lip is not a horse's mouth

it's time to adopt the Chinese working condition detection method

in fact, not only is the NEDC working condition method increasingly unsuitable for China's national conditions, but also Europe, its birthplace, has gradually felt its problems and began to reform. From 2008 to September 2017, the United Nations Economic Commission for Europe (UNECE) took 9 years to complete the wltc working condition and switched with NEDC in 2017. Wltc working condition has absorbed the standards of the United States and Japan in the formulation process, and China has also sent relevant personnel to participate, which is known as the world automobile working condition law. China's upcoming national six vehicle emission standard will be switched from national five NEDC cycle to wltc cycle

however, wltc mode method is still mainly the product of European "Continental conditions", which is still far from the actual situation in China. After its implementation, a three-year transition period has been reserved, and it will be officially implemented by 2020. After decades of development, China has become the world's largest auto production and consumption country, and it is time for China to achieve academic success and walk independently without teachers. Overtaking in the field of new energy vehicles is a Xintiandi opened up by China's automobile industry. The supporting "ten cities and thousands of vehicles" demonstration, promotion and application project, two-level government financial subsidies, charging infrastructure construction, market-oriented promotion, large-scale attempts to share travel, and the in-depth development to networking, intelligence, and green energy are all new exploration, new pursuit, new guidance, and new contributions of China to the development of the world's automobile industry. Accordingly, the inspection and testing standards and methods of new energy vehicles should also conform to this development law, China's national conditions and the needs of the Chinese market. It is against this background that Chinese working condition method was born

in January, 2015, the Ministry of industry and information technology issued the research project of "development of new energy working condition products of China's automobiles", entrusted China Automotive Technology Research Center to take the lead in organizing, and planned to invest sufficient funds in three years to support the development of working condition products in China. It is understood that the project team selected 41 representative cities, established a collection fleet of about 5500 vehicles (including light vehicles, heavy vehicles and new energy vehicles), and collected data on sports characteristics, dynamic characteristics and environmental characteristics of about 44 million kilometers. Among them, the cumulative mileage of traditional light vehicles, heavy vehicles and various new energy vehicles is 22.6 million kilometers, 14.9 million kilometers and 6.5 million kilometers respectively. In terms of test verification, 35 vehicle enterprises, engine enterprises and testing institutions participated in the verification of working conditions, and completed nearly 500 tests of more than 100 vehicles, including traditional passenger vehicles, ev (pure electric vehicles), PHEV (plug-in hybrid vehicles), light and heavy commercial vehicles, etc. In order to verify the accuracy of the data, the project team also compared the collected data with network traffic big data (didi trip, Gaode traffic) and Baidu GIS traffic volume big data (GIS)

the study of working conditions in China is divided into four parts: data collection, working condition development and standard formulation. From 2015 to 2017, the China Automotive Technology Research Center conducted a test and Research on the working conditions with the largest number of vehicles tested, the largest number of cities involved and the most data collected in the world, forming a complete "Chinese working conditions" including passenger cars, new energy vehicles and commercial vehicles. After the comparative test, the project team found that the fuel consumption measured under Chinese working conditions is 8% to 25% higher than the announced fuel consumption measured under NEDC working conditions, which indicates that the fuel consumption under Chinese working conditions is closer to the actual fuel consumption of the society, and that the working condition method of China electronic universal testing machine is more accurate, scientific, strict and realistic if oil leakage is found. It is understood that China's automobile driving cycle part 1: light vehicles has passed the consultation stage of national recommended standards. Its implementation will contribute to the scientificity, accuracy, impartiality and authority of the electric vehicle driving range announcement, and can effectively alleviate consumers' mileage anxiety

Copyright © 2011 JIN SHI