First of all, we have to understand what an engine is. An engine is a machine that can convert other forms of energy into mechanical energy. It is divided into internal combustion engines, external combustion engines, jet engines, electric motors, and so on. And our commonly used truck engine is a kind of internal combustion engine.
The engine was first born in the United Kingdom, and its original meaning was "mechanical devices that generate power". However, due to the rapid rise of the industrial revolution, environmental pollution problems have also come, so there are regulations on engine emission limit standards, and every emission upgrade , Are accompanied by the upgrade of engine emission standards. So far, my country’s emission standards have been upgraded six times. So what has the upgrade changed? Today we will briefly explain.
With the rapid development of the automobile industry, the number of automobiles has increased rapidly, and the problem of exhaust gas pollution has become increasingly serious. Starting in the 1960s and 1970s, countries have gradually introduced legislation on automobile exhaust emissions and adopted strict regulations to promote the progress of automobile emission control technology.
Automobile emissions refer to harmful gases such as CO (carbon monoxide), HC+NOx (hydrocarbons and nitrogen oxides), and PM (particulates, soot) emitted from automobile exhaust gas. They are all harmful gases produced by the engine in the process of combustion work.
"National One" began to be implemented nationwide on July 1, 2001. The "National One" standard refers to the "Euro One" standard, mainly for carbon monoxide, hydrocarbons and particulate emission limit requirements. Carbon monoxide is 3.16 grams per kilometer, and hydrocarbons is 1.13 grams per kilometer.
The "National Two" standard was implemented nationwide on July 1, 2004. The "National Second" standard has further increased the requirements for vehicle emissions. Starting from the Second National, the engine has been improved on the original technology, mainly using exhaust gas turbocharging and cooling technology to change emissions.
The "National Three" standard began to be implemented nationwide on July 1, 2007. In order to reduce pollutant emissions, the engine and exhaust system have been upgraded and modified in terms of technology, vehicle self-diagnosis system has been added, and the three-way catalysis has been upgraded.
The "National Four" standard began to be implemented nationwide on July 1, 2010. The post-emission treatment system has been upgraded, and the pollutant emission standards have been reduced by 50% to 60% compared with the "National Three". The real "exhaust post-treatment configuration" has also appeared in the National Three and National Four.
The "National Five" standard began to be implemented nationwide in 2018. The standard imposes more stringent restrictions on motor vehicle emissions such as carbon monoxide and suspended particles. It also increased the emission limits for non-methane hydrocarbons and PM, reducing air pollution.
Different from the previous five standards, the "National VI" standard sets up two stages, "National VI a" and "National VI b". Among them, "National VI a" will be implemented nationwide on July 1, 2020, and "National VI b" will be implemented nationwide on July 1, 2023. Compared with the "National V" emission standard limit, "National VI a" requires a 50% reduction in the carbon monoxide (CO) limit, while "National VI b" requires total hydrocarbons (THC), non-methane hydrocarbons (NMHC) and nitrogen oxides. (NOx) limits were reduced by 50%, 48.53% and 41.67% respectively.
During the 20 years from "National One" to "National Sixth", China's automobile emission standard system has been gradually established. At the same time, with the continuous improvement of environmental protection awareness, new energy vehicles have emerged, and the market share is increasing. The government has also actively promoted the development of new energy vehicles. With the rapid advancement of technology, core bottlenecks such as battery life are gradually resolved, which will also bring more challenges to the emission technology of fuel vehicles.