diesel exhaust post-processing controller
overview
diesel is burned in a high-temperature oxygen-rich environment, which is easy to cause an increase in nox emissions. therefore, nox is one of the most important components of diesel engines’ harmful emission. emission regulations are increasingly demanding to reduce nox emission. with the implementation of the national fifth-stage motor vehicle pollutant emission standards and the approaching implementation of the national sixth-stage motor vehicle pollutant emission standards, selective catalytic reduction (scr) will become a preferred solution for a large number of exhaust system production plants, diesel engines plants and even oems. the nature of the chemical reactions used in this technique is:
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the controller is the core component of the diesel exhaust post-processing system, and its control schematic is as follows:
diesel exhaust post-processing system includes:
• scr control unit
the scr control unit is electronic control unit of the diesel exhaust post-processing system (dcu), and the dcu communicates with other controllers via can.
• urea supply unit
used for the supply of the urea solution.
• air supply unit
used to assist the air supply.
• pre-oxidation catalyst convertor
placed in front of the scr catalyst convertor as a pre-processing unit for the engine exhaust, this convertor is used to adjust the exhaust to the appropriate working range.
• scr catalyst convertor
in the scr catalyst, the urea solution has a relatively complicated chemical reaction with nox.
• post-oxidation catalyst convertor
generally used to eliminate the leakage of ammonia.
functionality
the main functions of the scr control unit are as follows:
• obtain signals from other controllers through can
• various sensor signal acquisition
• urea injection volume calculation
• auxiliary air supply calculation
• drive various actuators
• diagnosis
advantages
compared with other competitive products, its main advantages are as follows:
• integrated urea injection volume calculation and urea pump motor control function;
• 32-bit mcu with high clock frequency and large storage space;
• resource-rich and high adaptability, in addition to the scr system, there have been successful cases applied to egr, electronic governor and dpf;
• uds-based bootloader;
• vehicle communication based on j1939;
• obd based on j1979;
• ip6k7, high protection level;
• anti-macadam-impact;
• back pressure protection.
product value
using this product can bring the following value to customers:
• align the customer's vehicle, diesel engine or exhaust system to meet the national fifth-stage motor vehicle pollutant emission standards and even the national sixth-stage motor vehicle pollutant emission standards for nox limits
• it is not only to provide customers with a hardware product, but also to build a product development platform for customers and provide support and services for the platform. customers can customize their own applications based on the platform, such as exhaust gas recirculation (egr) electronic governor and diesel particulate filter (dpf), etc.
• hirain can help customers complete system architecture design, detailed solution design, product implementation and verification for specific applications. it has successfully developed and supported post-processing control units for tenneco, weichai power, and faurecia.