In order to meet Euro II and Euro III emission standards, vehicles need to adopt different emission control technologies. In order to meet the Euro II standard, light-duty vehicles only need to install a three-way catalytic converter and improve the engine; and to meet the Euro III standard, it is necessary to adopt a better catalytic converter active layer, catalyst heating, and a catalytic converter. The installation location is close to the engine and new technologies such as secondary air injection. Obviously, compared with the Euro II standard, the emission control technology of the Euro III standard is much more complicated and difficult.
Key technologies that can be considered for light-duty vehicles meeting Euro III standards: three-way catalytic converter; engine improvement; better catalytic converter active layer; catalyst heating; catalytic converter installation location close to the engine; secondary air injection ; Exhaust gas recirculation system with cooling device; optimized combustion chamber vortex formation.
From Euro Ⅱ to Euro Ⅲ, the vehicle emission is not as simple as Euro Ⅰ to Euro Ⅱ. It is a step up and requires three technologies. The first is to increase the requirements for vehicle emission compliance during cold start. During the experiment, the vehicle was required to stand for more than six hours under a low temperature of minus 7 degrees Celsius. After the vehicle was ignited, the vehicle emissions were measured immediately to meet the standard. This technical requirement is not in the Euro II standard. It raises the requirement of exhaust gas purification catalyst, which is not met by the catalyst suitable for Euro II standard. Secondly, a special monitoring function (OBD, on-board diagnostic system) of the emission control system has been added to the vehicle's electronic control system. It can monitor vehicle exhaust emissions at any time, and will prompt if it exceeds the limit. This OBD is not available on Euro II standard vehicles. The third item is proposed for manufacturers, and it is necessary to have warranty measures for the on-board diagnostic system.
The biggest gap with Euro Ⅱ standard is that Euro Ⅲ begins to include cold-start emissions. Therefore, domestic gasoline engines will not meet the standard requirements even if they have adopted three-way catalytic converters. It is possible to upgrade vehicles that have reached Euro Ⅰ and Euro Ⅱ standards to Euro Ⅲ. The usual approach is to add a catalytic converter that reduces cold-start emissions, add intake air heating devices, and further improve the vehicle's electronic control system. Control accuracy of fuel mixture concentration. For diesel engines, exhaust gas recirculation, which is usually called EGR technology, electronic control technology, and turbocharged intercooling technology must be used, otherwise it will be difficult to meet the requirements. Domestic EGR technology is still in the development stage, turbocharged intercooling technology has begun to be used in cars, but electronic control has not yet begun. Therefore, if the emission level of domestic diesel engines reaches Euro III, more work needs to be done. In addition, the domestic fuel level must also keep up, such as providing low-olefin gasoline and low-sulfur diesel.
Compared with Euro Ⅰ and Euro Ⅱ, the Euro III standard has much stricter requirements and is a qualitative leap. It is an updated concept. Generally speaking, it is possible to meet the requirements of Euro Ⅱ vehicles after being improved. However, the key is to see whether the principle of the engine design is based on meeting Euro II, taking into account the requirements of Euro III, and whether it is possible to expand. The feasibility of other vehicles being improved to meet Euro III standards is very small.