Product Technical Approach
DPF (Diesel Particulate Filter) is also known as DPF Exhaust PostprocessingSystem, after a long time of particulate capturing, the porous media channelsof the filter will be blocked, which will result in an increase of back pressurewithin the exhaust system, thus affecting the normal operation of the engine. Therefore,it is necessary to adopt measures to remove the carbon soot particles filteredby DPF and restore the filtration capacity of the DPF, which is termed asregeneration. Regeneration approaches are generally categorized as active andpassive regenerations.
The products developed by Sinocat are designed to reduce theemission of pollutants such as CO and HC in exhaust gas through DOC catalyticoxidation reaction, while DOC oxidizes NO to NO2 in exhaust gas. At the propertemperature, the passive regeneration of PM captured by CDPF (a catalyticconverter coated with a layer of catalyst on a DPF carrier, known as CDPF) willbe realized. Upon fulfilling the conditions for active regeneration, thecontrol unit manages the injection device to inject fuel in front of the DOC,and the exhaust temperature is greatly increased by DOC, so that the PM in CDPFcan be regenerated. The catalytic performance of DOC and the filteringperformance of the CDPF contribute to the purification of exhaust gas.
The company’s products are tested according to the test standardof Ministry of Ecology and Environment, and industry test standard (HJ451-2008).The conversion efficiency of DOC of catalyst for HC and CO exceeds 80%, the capturingefficiency of DPF for particulate matter reaches more than 90%, while theregeneration efficiency of particulate matter attains over 90%.
The control unit monitors the temperature of the catalyst and thepressure difference before and after CDPF, and judges whether the regenerationis needed according to the carbon load and working conditions. If regenerationis needed, the controller will regulate the regeneration system and it isequipped with remote online monitoring device.
In view of the actual situation of diesel vehicle emissions inuse, the longitude and latitude of different regions and the temperature inwinter, Sinocat provides two different schemes of modifications, whose principaldifference lies in the varied regeneration technology approaches, so as to meetthe transformation requirements of diverse automobiles.
Adaptability of Fuel
The products of Sinocat can adapt toNational V stage for diesel automotive (sulfur content S≤10ppm)
Product Safety Requirements
Removing the muffler of the original vehicle, installing theproduct behind the engine exhaust manifold, and fixing it on the vehicle frame.While ensuring the installation space of catalytic muffler, the distance fromthe engine should be minimized. When necessary, the exhaust pipe should beinsulated, and the maximum distance after insulation should not exceed 2000mm.
After the installation of the product, it ensures that theoriginal safety performance of the vehicle is unchanged and meets the relevantsafety regulations. In view of safety of system control strategy, the controlsystem will mandatorily terminate the active regeneration of the product undersome special circumstances and occasions, including terminating the activeregeneration process after parking and in special occasions (such as gas stations,flammable and explosive places, etc.).
(2) Structural Safety
All products, mounting brackets and other accessories shall be made of materialsmeeting the strength requirements of the whole automobile, to prevent theproducts from fracturing and falling off by severe vibration during driving.The structure and size of the muffler are similar to those of the originalvehicle, which will not affect the original safety performance of the vehicle. Excellentinsulation measures are in place to prevent fire or personnel scald caused byhigh temperature.
(3) Security of Control Strategy
Precise regeneration condition evaluation ensures the product regeneration in atimely and effective manner. As a result, it is necessary to specify stringentregeneration condition threshold, including vehicle speed, exhaust temperature,CDPF back pressure, setting value of cumulative operation time for regeneration,and mandatory termination of active regeneration after parking or under specialoccasions (such as gas stations, flammable and explosive places, etc.). Thepower is taken from the standby terminal of the original vehicle, and thesystem will automatically power off after parking, without affecting theelectrical system of the vehicle. The system is equipped with its own gassource, therefore, there is no need to take gas from the original vehicle,which will by no means affect the braking performance of the vehicle.
The power is collected from the spare terminal of the original vehicle, and the system automatically loses power after parking, without affecting the electric system of the vehicle. With its own air source, the system does not need to take air from the original vehicle, and does not affect the braking performance of the vehicle.
DPF Exhaust Gas Post-treatmentSystem Combustor Type
Principle of Regeneration
The DPF exhaust gas post-treatment system combustor employs acombination of active + passive regenerative combustor scheme. As the passiveregeneration scheme is identical to that of the DPF exhaust gas post-treatmentsystem, it will not be presented here. The combustor ignition regenerationsystem utilizes operating time (8 hours of continuous operation) + pressure differenceto detect the carbon soot load in CDPF, thereby triggering active regeneration.By controlling the fuel injection volume, air intake volume, the controllerwill combust the injected fuel in the combustor and rapidly raise the exhaustgas temperature, so that the temperature at the inlet of CDPF can reach morethan 500°C and realize the active regeneration of CDPF.
In this system, a suitable operating condition is selected forregeneration, and closed-loop control is adopted to monitor the temperature atthe front and rear end of the DOC and regulate the fuel injection volume andair volume in order to ensure the required temperature for regeneration whileavoiding damage to the CDPF carrier by uncontrolled regeneration.
① Passive type of DPF exhaustgas post-treatment system
Ascan be seen from the figure above, the regeneration condition for products ofthis system is as follows: the regeneration of the combustor can be realized undermedium exhaust flow rate within 300℃.
Active RegenerationDevice Structure
Regeneration Control Strategy
The combustor ignition regeneration system utilizes operating time(8 hours of continuous operation) + pressure difference to detect the carbonsoot load in the CDPF, thereby triggering active regeneration. By controllingthe fuel injection volume, air intake volume and the fuel injected by theignition plug, the controller will combust the fuel in the combustor andrapidly raise the exhaust gas temperature, so that the temperature at the inletof CDPF can reach more than 500°C and realize the active regeneration of CDPF.
Thermal Management Scheme
Passive type of DPF exhaust gas post-treatment system
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