Do you know the cold knowledge of these automobile working condition tests?

I believe that except for local tyrants, most people are concerned about fuel consumption when buying a car. Usually, a yellow "Automobile Fuel Consumption Sign" will be posted on the glass of a new car, which reads fuel consumption XX L/ 100km. This is the fuel consumption of the Ministry of Industry and Information Technology, which can also be found online.

Many people will compare the fuel consumption values of different cars before buying a car, hoping to buy a car with the best use and fuel economy with the most economical money.

In fact, many consumers know that no matter how to drive, it is difficult to reach the official fuel consumption value. Gradually, the reference value brought by this number has become less, and the relevant departments have lost some credibility, which is mainly attributed to the "wrong" working condition test method.

How to do automobile working condition test in China?

In China, manufacturers test the emission level and cruising range of traditional fuel vehicles. They mainly put the vehicle on the testing machine to simulate the real situation and sample data at various speeds. But the problem is that the simulation of real working conditions is too simple. They can turn off the air conditioner and electronic equipment, and even increase the tire pressure to reduce the rolling resistance, thus achieving the ideal fuel consumption test value.

But in reality, it can't be so ideal. There will be friction, wind resistance and traffic jam in various road sections, which are difficult to simulate on the testing machine, so these values are of little significance to consumers.

The simulation test method adopted by China is NEDC standard, which is called "New European Driving Cycle", which is translated into Chinese as "New European Driving Cycle".

Although it is "new", it is not new at all. This standard was issued in 1980. At that time, it was mainly used to test European cars. Today, even Europeans don't use this method, but they change to WLTP.

NEDC mainly samples from low speed, medium speed and high speed, and there are few external environmental conditions, so the wind resistance is simulated by blower. There are several obvious problems. First, the unified vehicle condition accounts for a large proportion and has strong regularity, and the long-term stable driving state of the vehicle is quite different from the actual situation.

This driving mode is very common in Europe, but the working conditions in China are much more complicated. In addition, the test time of NEDC is short, and the test mileage is not long enough, and the influence of environment and temperature on vehicle running state is not considered.

Moreover, when NEDC came out, the electric car craze had not yet come, so the endurance test of electric cars was also "ideal", which was far from the actual driving. Some "experienced" old drivers said that if you want to buy an electric car, multiply its NEDC battery life by 0.7 or 0.75, which is almost equal to the actual battery life.

Therefore, China urgently needs to use more scientific and reasonable detection methods. However, since auto start is relatively late, it is necessary to refer to developed countries in automobile industry when formulating standards in this respect. At present, WLTP, EPA and JC08 standards are mainly popular in the world except NEDC.

It covers more average speed and speed variables than NEDC, especially in the duration of high-speed test, which can be compared by looking at the figure below. Therefore, the data sampled by WLTP is more accurate and closer to the level of people's daily driving. After about 20 17, Europe switched to WLTP.

The full name of EPA is "U.S. Environmental Protection Agency", which is currently recognized as the strictest and most accurate detection method. It has been tested in urban road conditions, high-speed road conditions and mixed road conditions, covering low, medium and high-speed, and considering other environmental variables, but the cost of doing so is relatively high.

JC08 is a test method adopted in Japan, which tends to step on the accelerator frequently and wait for traffic lights, emergency braking and suburban roads at any time. In fact, it is also close to the driving mode in many places in China, which should be closer than WLTP data. Unfortunately, JC08 has not become the mainstream test standard in the world.

China's own test method.

The full name of CATC is "China Automobile Inspection Cycle", which draws lessons from the inspection standards of developed countries such as NEDC and EPA, but the data collection is more subdivided and not as lazy as NEDC.

It is reported that the project team has collected a lot of data for the formulation of "Automobile Driving Situation in China". Among them, during the formulation of 1 part (light vehicles), a collection fleet of 3,832 vehicles was established in 4 1 representative cities.

Covering traditional passenger cars, light commercial vehicles and new energy vehicles, about 32.78 million kilometers of vehicle motion characteristics, dynamic characteristics and environmental characteristics data were collected; The data collection area covers the main areas of the country, except for first-and second-tier cities such as municipalities directly under the central government and provincial capitals, and also has good coverage for third-and fourth-tier cities;

The collection roads cover urban areas, suburbs, main roads, branches, expressways, secondary main roads and expressways, and the collection time covers working days, holidays, peak hours and peak hours in spring, summer, autumn and winter.

During the formulation of Part 2 (Heavy Commercial Vehicles), more than 65,438+0,200 heavy commercial vehicle collection fleets were established in 465,438+0 cities, and about 265,438+0,000 kilometers of relevant data were collected. It can be said that the collection fleet covers major cities and regions in China, covering different road types and driving conditions, and the collected vehicles cover various types.

Therefore, CATC tested different vehicles (light vehicles, heavy vehicles, private cars, official cars, taxis, etc.). ) At different speeds and road conditions, GIS traffic low-frequency dynamic big data of hundreds of thousands of roads in dozens of cities across the country were collected and compared with those of Baidu, Gaode and Didi. The final result, whether it is a fuel vehicle or a new energy vehicle, has more reference value.

In a word, CATC not only reflects the working conditions of different vehicles, but also studies the working conditions of engines, batteries and motors. The samples are more useful and more extensive. The establishment of these working condition standard systems has filled the gap in China's independent formulation of automobile working condition systems. In the future, when people buy a car, the official energy consumption value they see will not be as large as it is now.