National VII emissions are really coming, can we still rely on diesel engines?

Posted by bruce zhu on February 6th, 2022

Following the National VI emission standards, the concept of National Seven appeared. Recently, the State Council issued a document confirming that it is necessary to study and formulate emission standards and oil quality standards for light-duty vehicles and heavy-duty vehicles in the next stage. This means that more stringent emission standards than China VI are coming, and there is a high probability that it will be the so-called China Seven standards. Sinotruck howo So how strict will the National Seventh Standard be? How will our common truck be realized?

As we all know, our emission standards basically refer to European and American standards. Taking China VI as an example, we have integrated European and American standards, and then improved some standards based on them, and finally formed our China VI standard. . Judging from the severity of the two, our National VI standard is higher than the same period in Europe and the United States.

According to relevant information, the European Union has previously issued some limits for the Euro 7 standard. In the \"Letter to the European Commission Euro 7 Emission Industry\", it stated that the Euro 7 emission standard requires that the carbon monoxide emissions of the exhaust be reduced from the current 500-1000mg/km to 100-300mg/km, while nitrogen oxide emissions must be reduced to 30mg/km. At the same time, the proposal also proposes to install an engine diagnostic system on traditional fuel vehicles to monitor and ensure that they still meet emission standards within 150,000 miles (241,401 kilometers).

From the perspective of pollutant emission restrictions, our current most stringent China VI B standard carbon monoxide limit is 500mg/km, and nitrogen oxide emissions are 35mg/km. Judging from the current National VI standard, it is not difficult to find that our standard is basically the ceiling of Euro VI, and we have also taken the lead in adding a remote diagnostic monitoring system.

Therefore, we can simply judge our National 7 standard based on some limits of Euro 7. First of all, the emission of pollutants must be 3-5 times lower than the current National 6, and remote supervision will also be strengthened. Whether it is Euro 7 or National 7, the most important change is to lower the limit of emission pollutants to obtain cleaner exhaust gas.

When the Euro 7 standard came out, a Volkswagen engineer once said that according to the Euro 7 standard, the price of the car will be greatly increased. And the Euro 7 emission standard covers high-horsepower vehicles, such as trailers, which means the end of internal combustion engine vehicles. In fact, even 48V mild-hybrid vehicles cannot easily meet such requirements.

In addition, according to a previous interview with a Volkswagen engineer, he said, \"We will have to abolish the manual transmission model so that we can control the precise timing of the transmission gear switch, the acceleration performance of the vehicle will be reduced, it will be slower, the car will be like It\'s like taking sleeping pills. On the other hand, not only will the cost of the car company skyrocket, but all the fun associated with driving will disappear for the car.\"

As early as before the implementation of the National VI Standard, some relevant persons revealed that according to the current technical level of the global vehicle internal gas, it can no longer meet the requirements of the next stage. At present, the highest thermal efficiency of diesel engines for vehicles is about 51%. If the thermal efficiency does not increase, it means that the emission of pollutants cannot be reduced. For diesel engines, if they are improved on the basis of China VI, they will face even greater challenges. Technical Difficulties.

At present, there are two speculations in the industry. For models equipped with diesel engines, one is to improve thermal efficiency, improve the combustion effect of fuel, and reduce pollutant emissions. The other is to use a hybrid solution, which uses an electric motor to reduce the frequency and time of use of the diesel engine at certain vehicle speeds and speeds, so as to reduce the emission of pollutants per unit mileage to meet regulatory requirements.

According to previous announcements by the Ministry of Industry and Information Technology, many OEMs have begun to declare hybrid models with small-displacement engines and electric motors. In some respects, the models with hybrid solutions can also be understood as technical reserves and verifications for reducing pollutants. On the other hand, they can also help achieve the current dual-carbon goal.

In addition to the hybrid solution, pure electric and hydrogen fuel cells may also be the solutions for China VII in the future. According to the current use of pure electric and fuel cells, their emission pollutants are basically 0, so there is no so-called so-called the emission limit of pollutants. And according to the actions of major car companies in the field of hydrogen energy at this stage, the development of trial-produced vehicles has basically been completed, and some models have begun small-scale road test testing and calibration.

• Afterwords

Judging from the current National VI standard, if the National Seven Standard is further implemented in the later stage, it will be difficult to rely on diesel engines alone to achieve the National Seven emission standard with higher emission limits. According to many voices in the industry at this stage, if higher emission standards are to be achieved in the later stage, perhaps hybrid models will be a major solution.

Whether it is from the current emission regulations or the global consensus on green development, there will be more and more hybrid vehicles, new energy vehicles and clean energy vehicles in the future. What do you guys think about this?